NO. 1237. SYNOPSIS OF THE LUCINACEA—DALL. 785 



Genus AXINOPSIS G. O. Sars, 1878. 



Valves with one or more cardinal teeth; shell small, solid, with no 

 posterior dorsal area or plication, usually suborbicular. 



Type, A. orhiculatus Sars, 1878; not Luclna orhiculata Montagu, 

 1808 (as Venus)', + Kellia orbicularis Friele, 1877, not of Searles Wood, 

 1853. 



Genus LEPTAXINUS Verrill and Bush, 1898. 



Shell like Axinulus, but with distinct lateral teeth. 

 Type, L. minutus Verrill and Bush, 1898. 



? Genus LUDOVICIA Cossmann, 1887. 



Valves rounded-triangular, subcompressed, edentulous, with minute 

 prominent umbones. 



Type, L. squamula Cossmann, 1887, Parisian Eocene. 



It is possible that further researches may render it advisable to 

 include Montacuta in this family. 



SPECIES OF THE EAST AMERICAN COAST. 

 THYASIRA INSIGNIS Verrill and Bush (as Cryptodon), 1898. 



Grand Banks of Newfoundland to Cape Cod, Massachusetts, in 65 to 

 471 fathoms. 



Cryptodon xSami Verrill, 1880, not of Philippi, 1815, is synonymous. 



THYASIRA OVOIDEA Dall (as Cryptodon), 1889. 



Off Cape Fear, North Carolina, in 563 fathoms.^ 



THYASIRA GRANDIS Verrill (as Cryptodon), 1885. 



From latitude 38° 29' north, south to Yucatan Straits, on the Ameri- 

 can coast in 856 to 1,582 fathoms. Also on the coast of France in 820 

 fathoms. 



Cryptodon pyri for tnis Dall, 1886, and Sehizothcerus grandis Locard, 

 1896, are synonymous. The application of the name Schisot/um-us to 

 this species by Locard doubtless grew out of a confusion of Cryptodofi 

 Conrad, 18'S7 ( = fSchizothcm'usConvad, January 31, 1853, = Tresus Gray, 

 January 1, 1853) with Cryptodon Turton, 1822. 



THYASIRA GRANULOSA (Jeffreys as Axinus) Monterosato, 1874. 



Gulf of Mexico to Santa Lucia Island, West Indies, in 60 to 116 

 fathoms. Also Mediterranean, Bay of Biscay, and Canaries, in 19 to 

 645 fathoms. 



1 Figured in Proc. U. S. Nat. Mus., XII, pi. xiv, fig. 3. 



Proc. N. M. vol. xxiii 50 



