Proceedings of the United States National Museum

The term "free thoracic segments" is used to denote those segments of the thorax that are not fused to the head. This is in contrast to many of the earlier, and some of the contemporary, workers.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 147

148 PROCEEDINGS OF THE NATIONAL MUSEUM

HAWAIIAN ACANTHURID CALIGOIDS— LEWIS 149 of the two above hi the shape and size of the fourth thorax.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 149 from both of the above hi the shape and size of the fourth thoracic

Free from the thoracic bone-bearing segment of short female, narrower at junction with third segment than at transition to genital segment. Abdomen of the female short, the length about one fifth largest length of genital segment; width slightly greater than greatest length (Fig. 4c).

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 151

Greatest length of second segment more than two and a half times greatest width; proximal portion of. Fu'st segment short, forming articular surface for second segment; sharply pointed, posteriorly directed process projecting from posterior proximal surface of segment.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 153 Second part short, approximately one-third length of first part, taper-

154 PROCEEDINGS OF THE NATIONAL MUSEUM

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 155 curved manner from broad proximal to narrow distal surface. Second

156 PROCEEDINGS OF THE NATIONAL MUSEUM

HAWAIIAN ACANTHURID CALIGOIDS— LEWIS 157thorax, including frontal region, 1.84 mm.; greatest breadth, exclusive of thorax, including frontal region, 1.84 mm.; greatest width, excl. marginal flange, 1.84 mm. Eyes distinct, located in anterior quarter of cephalothorax, contiguous on mid-longitudinal axis of body (Fig. 6a).

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 159

Length of first segment slightly more than four times greatest width; lateral edges parallel for most of length, projection of proximal inner surface forming articular surface. First segment with small lobate projection from posterior surface only near middle of segment.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 161

Exopodite two-segmented, with a well-developed, two-parted process, with a blunt tip, arising from the fusion of the protopodite with the first segment of the exopodite and curving inwards. First two segments of exopodite approximately equal in size, both rounded distally, apex with well-developed, slightly curved membranous spine.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 163 on first segment with indistinct frilled membrane around base, frilled

Holotype: length from anterior end of body to posterior end of caudal shoulder, without setae, 2.30 mm. Maximum length of cephalothorax, including frontal region, 1.23 mm; maximum width of cephalothorax, without marginal margins, 1.15 mm.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 165

Median cephalothoracic area extending slightly posteriorly, slightly pastlateral areas, not projecting at junction of fourth thoracic bone-bearing segment. Division between cephalothorax and fourth thoracic bone-bearing segment distinct in male and immature females.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 167 one and a half times length of first, wider posteriorly than anteriorly

Third node present just posterior and medial to base, arising from small plate; third node with two minute setules (Fig. 8j). Postantennal process of immature female without ring-like base, spine heavier and shorter than that of male (Fig. 8k).

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 169 segment and terminal process more elongate than in male, more weakly

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 171

Slight median longitudinal furrow present extending posteriorly from the slight median depression of the large cross furrow on the posterior border of the thoracic region. The region of the bearing segment of the fourth thoracic leg was significantly reduced from the junction of the cephalothorax to the region of the attachment of the fourth thorax, adjacent to the anterior lateral surface of the genital segment. The fourth leg-bearing thoracic segment narrowed slightly inward from the widest point at the beginning of the genital segment.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 173

First segment wider in proximal region than at both ends, narrowing abruptly towards proximal end, gradually towards distal; distal end irregular. The distal surface of the first segment is concave, the posterior surface projects posteriorly as a spine-like projection with a blunt tip. Third segment and terminal process elongate, longer than the maximum length of the second segment, with two additional processes, a fusiform process on the back of the distal part.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 175 greater than that of distal end of third part. Fourth part curved

Exopodite three-segmented; greatest length of first segment equal to length of combined second and third segments. The combination of the two terms is used to indicate the condition of the genital segment in the holotype female specimen. The above characteristics were taken primarily from Wilson (1932) and were modified from descriptions of members of the genus Lepeophtheirus given by.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 181

Distal end of the first segment small, bipartite, forming articular surface for the second segment. Inner distal SM plane of the second segment with finger-like protrusion; process appears segmented but segment-like structures probably similar to heavily chitinized, plate-like structures with different adhesion Processes in most specunens curve around the second segment and appear as a normal adhesion surface, but the process is not attached to the second segment except at the proximal end.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 183

Spine-like process bent inwards, distal end rounded; two nodules present on inner proximal region, proximal nodule with three setules, distal nodule with four (fig. 12^). Postoral process of female and male flat, spine-like, located just lateral to base of oral cone and directed posteriorly. Second segment elongate, lateral margins irregularly convex; inner proximal sm face irregular, forming a ticular surface and site of attachment for muscle moving segment.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 185 Maxilliped of male similar to that of female except with small,

HAWAUAN ACANTHURID CALIGOIDS — LEWIS 187 Aberrant immature male specimen shown in figure lid (second

As Shiino (1954) points out, all the species possess characteristics in common with other members of the genus, but not in common with all the members. Female: Length from front of body to back of caudal rami, excluding setae, 2.48 mm. Male: Length from front of body to back of caudal rami, excluding setae, 1.64 mm.

HAWAIIAN ACANTHURID CALIGOIDS— LEWIS 189

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 191

Second segment about 1.3 times length of first, inner surface close to small but distinct concavity forming ball-and-socket joint with articular surface of first segment. Second segment short, with strongly curved, acute terminal process and small, flat, lobate accessory structure. Second segment of exopodite palm-shaped with three spines and plumes on distal surface.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 195 Because of the variety of characteristics that are exhibited by members

Cephalothorax of holotype female specimen elliptical, frontal region present but reduced to undivided, plate-like structure with distinct median depression of anterior margin. Median cephalothoracic region extending posteriorly well past posterior extensions of lateral regions, covering part of fourth thoracic bone-bearing segment. Fourth thoracic bone-bearing segment of holotype female specimen small, almost completely covered dorsally by median extension of thoracic region.

HAWAUAN ACANTHURID CALIGOIDS — LEWIS 197

Genital segment of holotype female specimen slightly wider than long, lateral margins broadly rounded, posterior lateral regions forming large lobe. Genital segment width of allotype male specimen subequal to length, lateral margins broadly rounded, posterior lateral regions forming smaller lobes than in female. Abdomen of holotype female specimen rudimentary, fused to posterior surface of genital segment; cleavage line indistinct except in one paratype specimen and interrupted in this specimen (fig. 15c).

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 199 on proximal inner surface. Division between segment and terminal

First segment of two-segmented exopodites, slightly longer than protopodite, proxima and distal margins irregular, outer distal corner with protruding, heavily chitinized knob and simple spinule. Second segment of exopodite pahn-shaped, proximal and inner margins continuous, irregular, distal margin with three spines and fluffy seta. Second segment short, with smaller spine from outer distal corner; third segment slightly longer than the second, broadly rounded, with two small spines on the outer lateral edge.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 203 Genus Dentigryps Wilson

Fourth thoracic bone-bearing segment and genital segment fused in female, covered by a single dorsal plate. Genital segment expanded, lateral areas broadly rounded, middle of posterior margin concave, not convex as in D. Fifth legs visible as long, pointed, unjoined, spine-like projections from ventral posterior lateral surface of genital segment.

HAWAUAN ACANTHURID CALIGOIDS — LEWIS 207

Distal end of terminal process strongly cm'ved; separation between terminal process and second segment clear, segment with small, spidery accessory process on inner margin at the intersection of segment and terminal process. Maxilliped of males resembles that of females except with a large projection in the center of the inner margin to receive the distal end of the terminal projection of the second segment when the segment is flexed. First segment with strongly developed terminal ridge on outer corner, ridge with row of minute stems along inner margin.

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The diagnosis comes mainly from Wilson (1907), with modifications based on the characteristics of the species described after his publication. Immature male taken by the author from the cyst on the dorsal fin of a specimen of Acanthurus triostegus sandvicensis Streets captured by the US. Immature male taken by the author from the cyst on the pectoral fin of a specimen of Diodon holocanthus Linnaeus donated by Honolulu Aquarium (USNM 105181).

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 213

The lateral borders of the thoracic leg-bearing segment are concave in the anterior part of the file specimen, convex posteriorly, bending strongly inward at the junction of the fourth leg-bearing thoracic segment. The lateral margins of the fourth leg-bearing thoracic segment of the youngest specimen are broadly rounded, the greatest width a little less than twice the greatest length. Posterior sinuses extending anterior junction of cephalothorax and second leg-bearing thoracic segment; posterior extensions of lateral cephalothoracic regions projecting to middle of second thoracic bearing segment.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 217

First segment two and a half times length of second in late encysted specimens, about twice length of second segment in recently extant specimen. First segment of older early encysted specimen similar to that of young, but distal part larger, much swollen, with adhesive pad on inner distal face sm*. Exopodite with two segments; First segment longer than second, lateral margins regularly convex, with single spine from distal outer lateral angle.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 225 The moult of the form described as the older early encystment

HAWAIIAN ACANTHURID CALIGOIDS – LEWIS 225 The molt of the form described as the older early encystment. 115 mann in the family Chondracanthidae, although Bassett-Smith (1899) and Wilson recognized its relationship to members of the Caligoida and placed it in the family Dichelesthiidae. Due to the similarities between the four genera, Norion is placed with these genera in the family Anthosomatidae, the latter being originally a subfamily of the family Dichelesthiidae.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 227 Body ovoid, anterior half, except cephalon, maxilliped-bearing seg-

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 229 ment. Genital segment expanded from anterior junction of fourth

Fu-st segment well developed, slightly longer than second, inner proximal surface projecting as well developed, lobed, articular.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 231

This was probably due to the posterior part of the body being covered by a single dorsal and paired ventral plate. The fusion of the first leg-bearing thoracic segment, the maxilliped segment, and the cephalon, in addition to the presence of dorsal plates, indicates that it is a species. Similarities of the single dorsal plate covering the posterior surface of the animal and the paired ventral plates found in A^.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 233

Third segment varying in length, though generally equal in length to supporting segment of second leg. The posterior part of the third segment flared slightly at the junction of the fourth thoracic segment which bears the leg. The anterior borders of the fourth leg-bearing segment are rounded, located medially at the junction of the third segment (fig. 24:C,d).

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 235

The distal end of the second antenna is degenerated in the adult, and appears to have been claw-like in the younger stages (Fig. 24^'). Maximum width is about two-thirds of maximum length, a distinct projection in the middle of the anterior margin, and a distinct groove extending from a slight depression on the distal margin to the proximal region of the appendage (Fig. 24:k). Third thoracic leg ovate, attached to posterior lateral surface of segment; \vitliout the median groove, but with a depression of the distal surface.

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 237 Fourth thoracic leg ovoid, much smaller than preceding thoracic

Zoological Results of the Cambridge Expedition to the Suez Canal 1924, XXX: Report on the Crustacea: Copepoda (coastal and semiparasitic).

HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 241 Randall, John E