570 
A. E. Terrill — Catalogue of Marine Mollusca. 
well-defined as some of the other so-called species, recognized hy 
him and others, in this genus. 
The original specimens were from off Martha’s Vineyard, 19 
fathoms, and east of Block Island, in 29 fathoms, 1871. It has also 
been dredged by us, of smaller size, in Massachusetts Bay, Casco 
Bay, and off Nova Scotia. Off George’s Bank, 430 fathoms ! — 
(Smith and Harger, 1872.) Labrador! (coll. Packard.) Gulf of 
Mexico, — Dali. 
Very large specimens of the typical C. obesus , several of them 
more than 15 mm broad, but mostly dead, were frequently dredged in 
1880, off Newport, R. I., in 12 to 20 fathoms; and at stations 865- 
871, 873, 876, and 877, 878, in 65 to 192 fathoms, south of Martha’s 
Vineyard and Newport, R. I. In 1881, it occurred at stations 918, 
919, 949, 991, 1035, 1038, 1040, in 34 to 146 fathoms. It is most 
common in 20 to 100 fathoms, but a dead shell occurred at station 
894, in 365 fathoms. 
Cryptodon Sarsii (Phil.). 
Axinus Sarsii M. Sars, Reise i Lofoten og Finmarken, 1849, Nyt. Mag. Naturvid., 
vi, [p. 48] (anatomy, etc.). 
G. O. Sars, op. cit.. p. 60, pi. 19, figs. 5 a, b. 
Cryptodon Sarsii Terrill. Proc. U. S. Nat. Mus., lii, p. 399, 1880. 
This is also regarded, by Jeffreys, as a variety of C. flexuosns. 
A single large dead specimen of a shell agreeing very closely with 
this form, as figured by G. O. Sars, was dredged by our party, in 
!ff79, off Cape Cod. 
Cryptodon SUbOVatUS? (Jeff.) Terrill. 
Axinus subovatus Jeffreys. Proc. Zool. Soc. London, 1881, p. 704, pi. 61, fig. 8. 
An exceedingly thin, delicate and very inequilateral shell, appar- 
ently identical with the species described by Jeffreys, occurred at 
station 891, in 500 fathoms. One specimen. 
Cryptodon ferruginosus (Forbes). 
Axinus ferruginosus G. 0. Sars, Moll. Reg. Arct. Norv., p. 63, pi. 19, figs. 10, a, b. 
Cryptodon ferruginosus t Terrill. Amer. Journ. ScL, xx. p. 392, Nov., 1880; Proc. U. 
S. Nat. Mus., iii, p. 400, 1880. 
Off Martha’s Vineyard, living specimens were taken at many sta- 
tions. They were nearly all thickly encrusted with iron-oxide, which 
adheres very tenaciously ; beneath this crust the shell is usually much 
