NO. 1139. DEEP-WATER MOLLUSCAVERHILL AND HUSH. 785 



CRYPTODON GRANDIS Verrill. 



Cryptodon grandis VERRILL, Trans. Conn. Acad., VI, p. 436, pi. XLIV, fig. 22, 1X85; 

 Expl. Albatrvxs, Report U. S. Com. Fish and Fisheries for 1883, p. 575, 18*. r >. 

 CALL, Bull. U. S. Nat. Mus., No. 37, p. 50, pi. XLVI, fig. 22, 1889. 



Schizothceru.8 grandis (pars) LOCARD, Campagne du " Caudan," Aunales de 1'Uni- 

 versitc de Lyou, p. 180, 1896. 



This large and interesting species, described in detail and well fig- 

 ured in tlie first article quoted above, is a true Cryptodon, although 

 very distinct from any of our other species. Therefore it seems strange 

 that M. Locard has referred it to the very different genus, SchizotJuvnis 

 of Conrad, which belongs to the Mactridre. He identifies without ques- 

 tion a single valve, dredged by the Caudan off the coast of France, in 

 1,710 meters, as our species. It is, therefore, doubtful whether his speci- 

 men is congeneric with ours, for the latter certainly has no affinity with 

 Schisotha'rus. 



One live specimen and a few separate valves were dredged at three 

 stations between 1ST. lat. 38 29', W. long. 73 9', and K lat. 35 9' 50", 

 W. long. 74 57' 40", in 938 to 1,582 fathoms, 1883-84. 



CRYPTODON INSIGNIS, new species. 



(Plate XCI, figs. 1,2.) 



Cryptodon sarsii VERRILL, Proc. U.S. Nat. Mus., Ill, p. 399, 1880; Trans. Conn. 

 Acad., V, p. 570, 1882. 



Shell unusually large and thick for the genus, opaque white or 

 tinged faintly with reddish internally. Outline somewhat variable, 

 usually broad-ovate or subquadrate, usually moderately swollen, some- 

 times rather compressed. Umbos moderately large, not very promi- 

 nent; beaks small and turned forward. Luuule cordate, rather large, 

 pretty well defined. The radial folds and lobes are less marked than 

 is usual in this genus. A well-marked fold or shallow undulation 

 extends from the beak to the posterior margin, opposite the scar of the 

 adductor muscle; anterior to this there is abroad, slightly raised ridge, 

 extending from the umbo to the siphonal lobe of the margin; in front 

 of this there is usually a broad faint depression of the surface which is 

 scarcely apparent in many specimens; a posterior groove runs close to 

 and nearly parallel with the postero-dorsal margin. The antero-dorsal 

 margin, in the lunular region, is straight or slightly incurved; the 

 anterior end is short, a little prominent below the lunule, and obtusely 

 rounded; the ventral margin, is very broadly rounded, usually with a 

 slightly more prominent lobe at or just behind the middle, with a more 

 decided but obtuse projection (siphonal lobe) farther back where it joins 

 the posterior margin, which is usually somewhat incurved, correspond- 

 ing to the external wave-like depression, becoming convex opposite the 

 posterior external fold; the postero-dorsal margin slopes rapidly from 

 the beak and is sometimes broadly rounded, and at others slightly con- 

 vex. The surface is covered with conspicuous, more or less irregular, 

 Proc. N. M. vol. xx 50 



