[167] CEPHALOPODS OP NOKTHEASTEEN COAST OF AMERICA. 377 



the motion of the wings of a butterfly. This fact, and its bright colors, 

 suggested the English name that I have applied to it. 



Three specimens, two very young, were taken by the writer and 

 party, of the United States Fish Commission, in the trawl-net, 30 miles 

 east from Cape Ann, Mass., in 110 fathoms, August, 1878. Two large 

 specimens were taken by us off Cape Cod in 94 and 122 fathoms, with 

 the bottom temperature 41° F., August and September, 1879. Eecently 

 we have taken it in deeper water (182-388 fathoms) about 100 miles 

 south of Martha's Vineyard. It was, in each case, associated with 

 Octopus Bairdii and Rossia sublevis. 



ROSSIA Owen. 



Bos&ia Owen, Trans. Zool. Soc, London, 1828 (t. Gray). 



Owen, in J. Koss, Second Arctic Voyage, Appendix, p. xcii, pi. 100, 1835. 

 D'Orbigny, Cephal. Acdtab., p. 242. 

 Gray, Catal. Moll. Brit. Mus., i, p. 88, 1849. 



Mantle edge free from the head, dorsally, with a small median angle, 

 it adheres to the head by a longitudinal connective cartilage having 

 three ridges, fitting into three grooves, which form an ovate or horse- 

 shoe-shaped cartilage on the back of the head; two elongated, simple, 

 cartilaginous ridges, one on each side, also fit into ovate pits on the 

 base of the siphon. A free eyelid is developed beneath the eye. Pupils 

 indented above. An aquiferous pore, on each side, between the third 

 and fourth pairs of arms. Xo olfactory crests. Tentacular arms more 

 or less retractile into cavities below the eyes; club well-developed, usu- 

 ally with numerous, nearly equal, minute suckers, in about eight rows; 

 rims not toothed ; borders scaled. 



The males differ from the females in having larger suckers on the mid- 

 dle of the lateral arms; both dorsal arms are slightly hectocotylized. 



Rossia Hyatti Vecrill. — (Hyatt's bob-tailed squid.) 



Verrill, Arner. Journ. Sci., vol. xvi, p. 208, 1878. 



Try on, Man. Conch., i, p. 160, 1879. (Description compiled from preceding.) 



Verrill, Amer. Jour. Sci., xix, p. 291, pi. 15, tigs. 1 and 2, April, 1880; Trans, 



Conn. Acad., v., p. 351, pi. 27, figs. 8, 9; pi. 30, fig. 1; pi. 31, figs. 1,2; pi. 46, 



fig. 5, 1881. 



Plate XXXV, figures 2, 5, 6. Plate XXXVI, figures 3-6. Plate XXXVII, figure 1. 



Body subcylindrical, usually broader posteriorly; in preserved speci- 

 mens variable in form according to contraction. Dorsal surface cov- 



