52G 



BULLETIN OF THE BUREAU OF FISHERIES. 



For this reason I have finally decided to follow Mayer in ranking spinosissima Stimpson as a variety of 

 longieomis Kroyer. I believe that Boeck's AUgina echinata is the same as Stimpson's A. spinbsis ima, 

 although Sars, Hansen, and Ortmann agree in uniting JEginella spinifera (Bell) with Stimpson's 

 species. 1 have examined several specimens from Labrador and New England, including some from 

 very near the type locality of spinosissima, and they agree perfectly with Stimpson's description, and 

 also the description and figures of A. echinata given by Boeck and by Sars in his Crustacea of Norway. 

 None of the forms 1 have seen agree with the description and figures of Mgina spinifera (Bell) given 

 in Sars's Crustacea of the Norwegian North Atlantic Expedition. 



Caprella geomctrica. juv.. Prehensile an- 

 gle of the 2nd gnathopod of a young 

 male. The larger figure is drawn from 

 a larger male from Woods Hoi*.'. Mass. 



Caprella g-eoinetrica .Say. 



Body unusually robust and devoid of tubercles on spines; head with a large spine pointing 

 anteriorly; antenna? stout, first pair much less than half the length of body, second joint much stouter 

 than third and nearly twice as long; flagellum shorter than peduncle and composed of about twelve 

 segments; second antenna? in adult male about two-thirds as long as first and fringed below with 



numerous long hairs; hand of first gnathopods with palm straight 

 and armed with a pair of spines at the well-defined upper angle; 

 second gnathopods in adult male, very short and stout, basal joint 

 several times smaller than hand; hand tumid, strongly convex in 

 front; palm strongly setose, with a strong spine at posterior end 

 and a blunt tooth < >r tubercle near base of finger; gills nearly round; 

 three posterior peraeopods stout, carpus as wide as long and about 

 a third the length of propodus; palms of propodi extending nearly 

 to base and defined above by a pair of spines; lower margins of 

 third and fourth thoracic segments produced into laminae. 



The color is very variable. Some individuals are nearly color- 

 less; others are uniformly reddish in color, and others again may 

 be variously mottled. 



Length of an adult male, 15mm. 



This is one of the most common species of amphipod on the 

 southern roast of New England. It is more rare north of Cape 

 Cod, and I have not met with it at all as far north as Maine. Southward it extends to Virginia and 

 perhaps farther. The females do not differ greatly from the males in the form of the body, but they 

 are of much smaller size and have the second antenna', as in young male, nearly as long as the tirst; 

 the second gnathopods are relatively smaller and more slender, the basal joint being several times 

 longer than broad; the hand is more like that of the first gnathopods than in the male; the palm 

 has only a small projection armed with a spine at the upper end, and is devoid of a prominent tubercle 

 near the base of the dactyl. As in the other species of the genus, the young males differ in several 

 respects from the adults; the antenna* are more nearly equal in length and the first and second joints 

 of the first pair are less tumid; the gills are more oval in outline; the hand of the second gnathopods 

 is less stout; there are two spinous projections instead of one near the upper end of the palm, and the 

 tubercle near the base ot the dactyl is small or absent. This species has been united with ( '. acutifrons 

 Latreille, by Mayer. The two varieties of acutifrons which Mayer designates carolinensis and Virginia 

 doubtless belong to the same species that Say described as geometrica. The differences between these 

 varieties are small and are for the most part such as occur between indi- 

 viduals of different ages. These varieties, however, present certain differ- \ \ y~ x t 

 ences from the typical form of acutifrons, which appear to lie constant, and 

 it seems best, therefore, to retain for them the name given by Say. 



Caprella linearis Linna?us. 



Body rather slender, smooth above except on some of the posterior 

 segments, which may be furnished with tubercles or even short spines; eyes Cajlt 

 small, round; first antenna? stout, about half the length of body; joints of the 



peduncle finely ciliated in adult male; first and third basal joints subequal and shorter than second; 

 tiagellum shorter than peduncle; second antenna- sometimes longer than peduncle of first in female, 



