The width of the theradula from base to base of the opposing tooth is approximately one centimeter. Laterally from each auricle, a funicular muscular tube extends into a spacious sinus in the wall of the mantle. Leaving a fuller description of the gill for later, attention may be drawn to the parts surrounding the mouth.
Just behind the anterior adductor, two or more jiouch-like sacs can be seen on each side in front. The inner mnrgin of the shell is . smooth, the valves very unequal and tightly closed. In the mantle lobes behind the siphon there is nothing corresponding to the muscular regions of Euciroa.
The retractors of the foot are 'double on each side and are more than half their length.
NORTHWEST AMERICAN SPECIES
Station 3253, in Bering Sea north of the eastern Aleutians, in 36 fathoms near the Pribilof Islands; lowest temperature 35° F.; also on the south side of the Aleutians in the Pacific south of Unimak. Station 3227, in Bering Sea north of the eastern Aleutians, in 225 fathoms, green mud; lowest temperature 38.6° F. Station 3202, in Bering Sea north of Akutan Island, in 43 fathoms, sand; temperature 41°F. Station 3330, in Bering Sea north of the eastern Aleutians, in 351 fathoms, sand; temperature38.2° F. Also in the Pacific south of Uni-.
Shell resembling Remithijris, Orbigny, from which itis is distinguished by having the inner upper edges of the crura extended towards each. From the top of the inner edges of the crura on each side is given an excavated lamina ofi', which. CONTINUATION OF THE NATIONAL MUSEUM.. reaches the median line above the septum, to which and to each other the himiuae are firmly attached, forming narrow spoiidylium.
The . The leading edge of the spondylium is mesially indented and there is an upwardly extending mesial line, on either side of which, in old specimens, the laminum is prominently shown by a callous deposit. On either side of the septum, between the septum and the supporting dental lamina, a pointed recess extends beneath the spondylium toward the cardinal margin. The surface of this valve, like that of the others, is too polished to retain many of the muscular impressions.
Frieleia cruralie at the apex of an arch, one arm of which joins the side of the valve, and the other unites with the keel of the septum, leaving a triangular surface, the apex of which is on the sejitum, the base forming the cardinal margin, and the sides the inner arms of the two arches. In well-developed adults, the suture of the spondyl is completely coalesced, and only a notch on the anterior edge and a groove on the upper surface show separation. The second repaired the damage caused by an extensive break with the shell substance shell, indicating that the shedding of shell substance is not limited to the peripheral parts of the mantle.
PROCEEDINGS OF THE NATIONAL MUSEUM. 719
But the deep-water excavations of the albatross have furnished a sufficient series of normally cultivated specimens of all ages and sizes, and I have, after a careful comparison of many specimens from each region, convinced myself that there is no good ground for a separation of them, even black. Strait; in 309fathomsoft" the island of Unalaska in the Bering Sea; and 240 fathoms off Santa Cruz, Cal.; temperature, 38° to 44° F. Also from the coast of the province of Kii, Japan, Stearns; and from the Philippine Islands, NE. It may possibly be known by its rounder outline, larger size and the fact that the sculpture of the peripheral parts of the shell becomes obsolete, and is represented by grooves with flattened,.
These can again be separated into at least two generic groups, DaUlna, by Beecher (apparently descended from Antiptychina, Zittel), which include those with a continuous cardinal plate, strong median septum in the brachial valve, and no fulcrums for the teeth on the pedicle valve. The second group includes Eudesia and Macandrevia and has the pedicle valve cavity below the hinge separated into three cavities by two buttresses that support. As far as is known, the only differences between them consist in the smooth surface of the valves and the weak brachial septum.
These hardly raise the latter above the subgeneric rank, since the plication of the valves in them is often inconstant. If the beak of the brachial valve of an old individual were ground off, the septum would be very noticeable. as found by Oehlerttor the beak of Endcsia cardium. The writer already has evidence that there are several species in . deep water, range from the Bering Sea southward to near the Grala])agos Islands, and in the case of one species, Solemyajohnsoniy Dall, more than a thousand miles to the south, with the known great range of many brachiopods, there would be no obvious reason why.
722 DEEP WATER MOLLVSKS AND BRACniOrOVS—BALL, yolivu. . recurved short beak, rather large foramen incomplete at the base to an extent of about one-fourth of its circumference, with a small obsolete deltidial plate on each side; teeth strong, short, each by a strong buttress with a recess behind it, and in old specimens with a smooth deposit of calcareous on the snr face of the valve between the two buttresses; no median septum, the nniscnl impressions faint, situated in the upper fourth of the valve; brachial valve plate, orbicular,Avith a small very low cardinal process produced downwards, three times its .. width, on the surface of the bill between the cortical plates, as a low ridge rounded above; crustal plates strong, supported by buttresses over half their length, rather close together, supporting a thin delicate brachidium, longitudinally grooved near and at the recurvation, with a few spinules on the outer edge, the haemal edge of the arch of the loop showing a small projection opposite the crural ])assion of each .. side, the brachidium reaching three-quarters of the distance froui the cardinal border to the basal margin and over all one-third as broad as the valve; pallial sinuses following much the same course in M.venasa, but straight, less branched, and of a whitish instead of reddish-brown colour. 723. greediness of the shell arises; teeth strong, foramen large, incomplete, the deltidia almost linear, but long; tooth supports strong, retracting as they approach the arch of the valve; brachial valve flatter; teeth strong, with many oblique cusps; brachidium four-fifteenths the length of the valve, scarcely one-third as wide as the valve, slender, with a single spine at the point of repetition, and a slight thickening, but nasal septum, at the cardinal apex; muscle impressions small and confined to the upper fourth of the valve. 122858, TJ.S.N.M. This species resembles MageUania [Waldheimia) wyvillei, Davidson, but wants the septum and cardinal process of the brachial valve of that species, which also has less oblique, shorter, and wider deltidia.
MACANDREVIA
The loop as a whole is very strong, but the connecting bands which join it to the lower branches of the brachydium are narrow and rather fragile; they probably got lost in the speci-. Albatros excavations have shown that the northern shell also occurs in the south in the same area and depth as the typical califoriiicus and without transitions in color and shape. Before the development of the loop in Terehratellidwu was fully understood, the similarity of some specimens of the meuiiform stage of Dallinasejj-tif/eratothose of L.jeffreysiledmetothose ofL.jeffreysiledmeto the question whether the latter might not become part of both o(;eans, but later Avhen different stages, through which D.
Shell scarlet, radiantly streaked with pale yellow, especially in the channels between the ribs; surface polished, smooth except for rather distinct incremental lines and, in mature specimens more or less distinct, partially obsolete radial ribs, occurring near the margin but not extending to the earlier half of the shell; in senile specimens a greater part of the shell is ribbed; pedicle valve with a rather low beak and wide, incomplete foramen; deltidial plates well developed but widely separated; valve wider (as a rule) below the middle, the. The various forms which the brachidium assumes during development have been fully illustrated and described by Beecher in the paper already quoted. Subsequently, a good amount of material from the vicinity of Cerros Island showed that the two species were completely distinct from each other. .. T. obsolete has no very close relative in the North Pacific.
It is possible that this locality is in error, but the species has a different sculpture than T. obsoleta and has only a slight reddish tinge to the overall brownish color. There is one characteristic, however. it is constant in the whole multitude of specimens which I have examined; the curvature of the middle of the valves is present, although often weak. always concave in the brachial valve and convex in the pedicle valve. We hope that the present reflguration will finally clear up the confusion. occidentalis in the adult state if attention is paid to the diagnostic characters, but there are others from which it is less clearly distinguished. jrayi, Davidson, from Japan, the southern reddish transversus specimens are difficult to distinguish outside.
It is possible that future research may discover T. gouldii on the American Pacific coast, as TerebratulinaIciiensis. is found thus scattered. Euciroapacifica, Dall, about twice natural size; diagram showing vertical cross-section of animal behind legs; o, 6, the subumbonal parts of the ticeral mass, showing the superficial region occupied by the genital glands, between which are seen the dorsalmant ends and the proliferations enveloping the teeth; c, pericardial chamber, with /(, the ventricle of the heart over the right side and partially extended v', the right ear, while v, the left ear, is fully exposed; below the ventricle is seen the rectum r, which passes through the floor of the pericardium and the incision of the transverse thick, in the lower transverse part; formed by a sheath of the mantle below the pericardium, from the lower inner wall of fine reticular fibers radiate upwards; this layer would appear analogous to the free nephridiallamine helicardium (fig. 3, s'n'), but attached to the visceral mass and shows the hardening of which does not resemble the jelly of the gills (with two tubular blood channels), supporting the transverse throat, on the faces of which the radiating lines represent , notplications, but the traditionation of muscular fibers through the transparent epithelium of the plates; the gill plates are represented as elongated laterally, but during life they extend obliquely backwards, just like the correct incisions of the plate outside their line; .. the dark shaded spaces above the gills are the anterior parts of the anal chamber;/, leg, above which the circular part of the retractor muscle is visible; m, m', mantle lobe, showing the columnar section of the muscular fibres. Halicardiaflexttosa, A^erhill, magnified about four diameters, diagram of vertical section of part of gill and gill, taken behind leg looking at siphons ; d, subumbonalevisceral mass;ov, cavernous nephridium which are seenj), q, Ijranches of retractor muscles, andcv, cavities in the general mass of partly glandular and partly fibrous tissue; c7; roof ap, posterior part of the anal chamber;s, downward continuation of the thenephridium; no,. the point where the free lamina is given abroad;
HalicardiajlcxHosa, Verrill, slightly enlarged; diagram of soft parts removed from shell, side view; a, median papilla above&, analsiphon; .. o-e,outside,pedal openings between mantle lobes; the ends of the muscles are shaded. Spergo glandiniformis, Dall; diagrams, a, i, d, natural size; e, slightly enlarged;/,about twice natural size;/j,strongly enlarged; a, anterior view of snout showing proportional position of tentacle; h, side view of crawling animal; d, anterior edge of foot from below; e, the rim rests on the back of the animal with the point turned away from the head; h, teeth, the upper pair placed in their natural position as they appear on the radula; the base of the tooth is shaded with spots; outside is a narrow fibrous band by which the teeth are attached to the radula; the blades are shaded; from cameralucida sketches by W. H. Dall; page 680.
