1888.] NATURAL SCIENCES OF PHILADELPHIA. 12.5 



He picked up a few recently dead Lady-crabs, Platyonichus oceUafus, 

 and found in them a number of the Cirolana concharum, feasting- 

 upon tlie flesh and other parts, as he had previously noticed them 

 feeding on the edible crab. See page 80. From these observations 

 it would appear to be the usual habit of the Cirolana to i^rey on 

 dead crabs and j^robably other animals. 



Parasites of the Striped Bass. — Prof. Leidy exhibited numerous 

 specimens of a minute crustacean parasite from, the gills of the Striped 

 Bass or Rock-fisl), (Lahrax litieatus), brought to our market. He 

 said it is a common parasite and he had been familiar with it since 

 1851. It was described by the Danish naturalist. Dr. Henrik 

 Kro3"er, under the name ot Ergasiluf< labricis, obtained from the same 

 fish at Baltimore, (Danske Naturh. Tids. 1868-4, 303, Tab. xi, fig. 2). 

 Common as it seems to be Mr. R. Rathbun, in his published list of 

 the parasitic Cojiepoda from American waters, says he had not ob- 

 served it, (Proc. U. S. Nat. ^NIus. 1881, 483). The little crustacean 

 lives suspended on the outer surfaces of the gills, where it is conspic- 

 uous, from the white color of its thorax and egg-pouches on the red 

 cohjr of the gills. The length of the parasite together with its egg- 

 pouches is 2-125 mm; without the latter 1*25 mm. 



Prof. Leidy further exhibited portions of two intestines of the 

 same fish with numerous attached worms pertaining to Echiuorlnjn- 

 chiis proteus, which infested many fishes, both of fresh and salt water, 

 of Europe. It is not only a frequent and abundant but a constant 

 parasite of our Striped Bass. It ranges from 5 lines to an inch in 

 length. The young ones are white; the older have the body yellow, 

 bright orange, or brownish orange, with a white neck and proboscis, 

 which together are one fourth the entire length. Diesing attributes 

 to the ])r()l)oscis 8 to 10 rows of hooks, but Dujardin gives double 

 the number, and this accords with the condition observed in our 

 specimens. The parasite lives in the large intestine with the pro- 

 boscis and neck together embedded in the wall and the body sus- 

 pended in the cavity. The proboscis and bulbous commencement 

 of the neck together protrude externally and form on the outside 

 of the intestine brown pyriform tumours, giving to the organ a 

 peculiar tubercular appearance. The worms exhil)it the following 

 characters: Body widest at the commencement, where it is rounded 

 and slightly constricted from the rest, which tapers to the posterior 

 obtuse end. Proboscis cylindrical but expanded at the middle and 

 base. Neck verv lono:, bulbous at the commencement becominsc 

 narrow and cylindrical and a little dilated at the base; smooth 

 throughout. Length of a large one 24 mm ; proboscis and neck 6 

 mm ; proboscis 1-25 mm long, 0-175 thick, 0-25 at middle expansion ; 

 bull) of the neck 1 mm, narrow part below 0'375 thick, at base 0'5 

 thick. Body at com.mencemeut 2 mm thick, near posterior end 

 1 mm thick. 



