These include three of the longest rivers east of the Alleghenies—the Susquehanna, the Potomac, and the James. The first type of Temora was found at the three stations at the mouth of the bay and also at station Y near the extreme inner end of the bay.
AKT. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 1 1
It also appeared abundantly in the outer bay in autumn and winter, and in the inner bay. Pseudocalanus was more of a winter species in the outer bay and a spring species in the inner bay.
BREEDING SEASONS
It was also obtained in summer, both on the surface and on the bottom, at the hundred fathom line in the outer ocean. The remainder showed a mixed seasonal distribution, with one season often more abundant in the outer bay and the other season in the inner bay.
ABT. 15 COPEPOD CBUSTACEANS OF CHESAPEAKE BAY WILSON 15
No stages of development were found at any of the stations near the inner end of the bay, but no positive statement can be made as to the ability of any of the copepods to breed in water of low salinity. However, data show that water with higher salinity is more favorable for breeding purposes, since development.
TRIP TO 100-FATHOM LINE
ART. 15 COPEPOD CRUSTACEAN'S OF CHESAPEAKE BAY WILSON 17
The Corycaeus species are small and only appeared in the surface net at the 100 fathom. Oithona plumifera and Rhincalanus nasutus are all oceanic forms unlikely to be found in the bay unless near the mouth.
DISCUSSION OF THE SPECIES
Of these seven species that occur most often in the sea, only one, Metridia lucens, was not also found in the bay. The few specimens obtained in one of the bottom nets at Station S in the inner bay were evidently exceptional.
ART. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 19 Suborder CALANOIDA
Herdman in 1897, these two species of Acartia were carried along the English and American coasts, but completely disappeared in the open ocean. Not infrequently, however, the current brings it close to the shore; and is even often found. In addition, it is just as abundant in the salty water of the inner gulf as in the outer gulf, whose salinity is almost as high as that of the ocean.
Although its ratio to clausii is usually the 2:8 ratio already mentioned, it often drops to 20, 10, or even 5 percent. A pelagic form, probably not found in the gulf, but not previously reported from American shores.
ART. 15 COPEPOD CRUSTACEAN'S OF CHESAPEAKE BAY WILSON 21 ANOMALOCERA PATERSONI Tcmpleton
Incident. - Found at Station S during one of the Bay's two largest catches using a bottom net on March 29 in 75 feet of water. This copepod was captured both on the surface and in the bottom net in the outer ocean. It seems like it might one day be found in other places, especially the Outer Bay.
They appear more abundantly during winter in the outer bay and during spring in the inner bay. Taken indiscriminately in surface, bottom and vertical nets, and also present in the outer ocean.
ABT. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 23
Occurred.- Found at two stations at the mouth of the bay and. at six stations in the inner bay, but not taken in the outer ocean. They occur nee.—^Widely distributed in the inner gulf, but only sparingly in the outer gulf; found most abundant at Station Z in water 13 feet deep on a muddy bottom. This is a brackish water species, which explains why . it is much more abundant in the inner gulf.. making it one of the most important constituents of plankton.
Occurrence.-Universally distributed in the outer bay, rarely in the inner bay, usually caught in the bottom net, but also taken on the surface. Most abundant in autumn, especially in the inner bay, but also present in summer and winter in the outer bay and on the surface of the outer ocean in summer.
ABT. 15 COPEPOD CRUSTACEANS OP CHESAPEAKE BAY WILSON 25 LABIDOCERA WOLLASTONI (Lubbock)
Prevent. - Found at every station in the bay except T and U, usually in considerable abundance in the outer bay, but gradually decreasing in number towards the inner end of the bay. It is also a thin lamina, extending anteriorly above the surface of the fourth and third segments, almost to the posterior margin of the second segment. The antennae and mouthparts are similar to those of other species of the genus, with certain variations.
Chief among the latter are the differences in the masticatory blade of the mandible. The lobes on the posterior corners of the last thoracic segment are markedly asymmetric, the right one is much longer and more sharply pointed.
ART. 15 COPEPOD CEUSTACEANS OF CHESAPEAKE BAY WILSON 29
In a plankton series collected by Herdman continuously over the North Atlantic, this species was very common around both shores and was also taken in mid-ocean. Left caudal ramus considerably longer than the right and bent outwards, six and a half times as long as broad; right ramus straight. The plumose setae at the ends of the rami are each joined near the middle and swollen before and behind the joint.
Each egg-sac female carried a large left sac, containing about 25 eggs, and a minute right sac, containing only two eggs. 3-segmented, the basal segment much shorter than either of the other two, the terminal segment terminating in three very long plumose clusters.
ABT. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 31
Farran ^ said of this species: "As regards its distribution over the greater part of the Atlantic, it can. North Atlantic, but is easily recognized by the sharp projections on the posterior corners of the fourth thoracic segment, the asymmetry-. Occurrence.— Taken in small numbers in bottom and vertical nets at stations E, F and G at the mouth of the bay and in vertical net at Y station.
Narragansett Bay, but Fish listed it as one of the three typical winter forms at Woods Hole. Its presence at both ends of the bay indicates that it can be found anywhere in the bay at times.
ART. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 33 TEMORA TURBINATA (Dana)
Caudal rami was tapered so that the points are approximately half the width of the base. The exopod of the second antennae is of the same length as the endopod and consists of seven segments, and both rami are armed with stout hairs. Maxillae and maxilliped resemble those of other species of the genus, with minor differences.
Fourth legs slender, endopod much longer than exopod, with small and relatively weak spines on distal inner corners of first two. It does not occur in sufficient abundance to give it any economic importance in breast life.
ART. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 35 CLETODES LONGICAUDATUS (Boeck)
Occurred.—^Well distributed, especially in the inner bay, where it was found at most stations. It is usually taken on the bottom net in the outer bay, but often on the surface in the inner bay. This small copepod is found in sufficient numbers in the inner gulf to form an important constituent of the plankton.
Occurrence.— About 30 specimens of this species, all females, were taken in the bottom net at Station Y, January 27, 1921, from water 20 feet deep over a muddy bottom; this is the only record for the bay. Like the other species of the genus, it is a coastal form and lives in the shallow and less saline waters.
AKT. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 37
Sars found only the female, but Brian added the male of the species, and the present specimens in-. Specific characters of the male.— Body regions similar to those of the female, posterior body rather more robust; its segments fringed on their posterior margins with slender spines, especially prominent on the ventral surface. Endopod of first legs much longer than exopod, with three finger-like processes on outer margin of second segment.
A pair of rudimentary sixth legs on the ventral surface of the genitalia just behind the median suture, each consisting of a small knob tipped with three setae. The main points of difference are found in the general body shape, especially the proportions of the various parts, and in the details of the second antennae, mandible and second legs.
ABT. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY — WILSON 41
Anterior half of genital segment expanded laterally to almost twice width of posterior half. Specific characters of males.— Cephalothorax one-fifth longer than wide and also one-fifth longer than the rest of the body. In Giesbrecht's figure of the male, the head is only one-fifth longer than wide, but is almost twice as long as the re-.
Egg cases are elongated-oval in shape and reach the anterior edge of the last abdominal segment. The type species of the genus purpureus was found by Sars in the Christiana Fiord on the.
ART. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WILSON 47
Occurrence.— Taken at every station in the bay except U, abundant everywhere and sometimes constituting 50 per cent or more of the total catch. Occurrence.-This head peut is not found within the limits of the. bay, but many specimens were obtained in the lower net from depths of 20 and 118 fathoms in the outer ocean. Occurrence.— One hundred specimens were obtained at the surface on the 100-fathom line in the outer ocean and 150 in the bottom.
OcGurrenoe. -Several specimens were obtained in the surface net of Station G at the mouth of the bay on October 21, and in the vertical net on December 4, 1920. Of the 15 lots of this species already in the collection .. of the United States National Museum, 9 were obtained from the tow.
52 PEOCEEDINGS OF THE NATIONAL MUSEUM VOL. 80
SPECIMENS DEPOSITED IN THE UNITED STATES NATIONAL. MUSEUM AND INDEX OF SPECIES
Specimens of Copepods Reported on in this Paper, Deposited in the United States National Museum, and Species Index*— Continued. Specimens of Copepods Reported on in this Paper Deposited in the United States National Museum, and Index of Species—Continued.
