NO. 1237. SYNOPSIS OF THE L UCINA CEA—DALL. 787 



THYASIRA CONIA Dall and Simpson, igoi. 



Off San Juan de Porto Rico, in 310 fathoms. 



THYASIRA CROULINENSIS Jeffreys (as Clausina), 1847. 



West Greenland, in 190 fathoms, Posselt; off Bermuda, in 435 fath- 

 oms. Challenger expedition; North Atlantic, Norway to the Azores, 

 in 30 to 1,012 fathoms. 



Axlnus pusillus M. Sars (manuscript?) is said b}- G. O. Sars to be 

 synonymous. 



THYASIRA EQUALIS Verrill and Bush (as Cryp'.odon), 1898. 



Nova Scotia to Chesapeake Bay, in 91 to 1,537 fathoms. 



Cryptodon crouUnensla var. altus Verrill and Bush, 1898, differs, 

 according- to the types, from this species by a longer and straighter 

 anterior slope, but this character is shown by a large series to be incon- 

 stant. It occurs in the Gulf of Maine and south to Cape Cod, in 14 

 to 35 fathoms. 



THYASIRA ROTUNDA Jeffreys (as Axinus), 1881. 



Abyssal in the North Atlantic, and liable to be found in deep water 

 on the American coast. 



Axlmis jlexuosus var. rotunda Jeffreys.^ This form is near to T. 

 equalis Verrill and Bush, but is less truncate behind. 



THYASIRA (AXINULUS) BREVIS Verrill and Bush, 1898. 



Georges Banks, off' Cape Cod, and south to the coast of North Caro- 

 lina, in 100 to 1,825 fathoms. 



Cryptodon obsoletus Verrill and Bush, 1898, is identical with this 

 species, and the differences in the figures, especially as to the position 

 of the ligament, are due to a misconception of the artist and the trans- 

 lucency of the very minute shell. 



THYASIRA (AXINULUS) FERRUGINOSA Forbes (as Kellia), 1844. 



Arctic seas, North Atlantic south to North Carolina on the west, 

 and the Azores, Mediterranean, Adriatic, and the Mortni on the east, 

 in 20 to 1,525 fathoms; also in Bering Sea, Krause. 



According to Jeffreys the Kellia trmhwersa Forbes (1841, Aegean) 

 and the Axinus ohlongus Monterosato are the young of this species, 

 which is relativel}^ more transverse than the adult, and the same is 

 probably true of the types of Cryptodon [Aximdus) ovatiis Verrill and 

 Bush, 1898, which in addition are abjiormally modified b}^ an excessive 

 load of oxide of iron. Specimens })urporting to be the same, from 

 station 2113, U. S. Fish Connnission, are apparently identical with T. 



^ Proc. Zool. Soc. London, 1881, p. 701. 



