NO. 1139. DEEP-WATER MOLLVKCA TEKUILL AND BUSff. 793 



The hinge-margin in the right valve is slightly thickened with a dis- 

 tinct, tootn-like prominence below and slightly in front of the center of 

 the beak, and an inner fold like thickening of the posterior margin to 

 support the ligament; in front of the lunular area the margin is con 

 vex and slightly everted. 



Length, about 1.6 mm.; height, about 1.4 mm. 



A few live specimens were found at three stations between ET. lat. 47 

 40', W. long. 47 35' 30", and X. lat, 39 54' 30", W. long. 70 20', in 

 206 to 499 fathoms, 1883-1886. 



This species is allied to C. ferruginostts (Forbes), from which it differs 

 in its distinctly produced and angulated posterior end, and longer or 

 more produced, evenly rounded anterior end. It also has considerable 

 resemblance in form to C. tortuos-us Jeffreys, but that has a very lus- 

 trous surface and more vitreous texture, and moreover entirely lacks 

 the posterior angulation. 



C. suboratus of Jeffreys, seems to resemble rather closely the small 

 specimens of this species, but that has more prominent beaks, is 

 wedge-shaped, the antero-dorsal margin sloping pretty rapidly from 

 the beak, instead of being nearly straight and horizontal as in our 

 species. 



CRYPTODON (AXINULUS) FERRUGINOSUS (Forbes). 

 (Plate LXXXVII, figs. 7, 8.) 



Cryptodon ferruginosus VERRILL, Trans. Conn. Acad., V, p. 570, 1882; VI, p. 279, 

 1884; Expl. Albatross, Report U. S. Com. Fish and Fisheries for 1883, p. 575, 

 1885. BALL, Bull. U. S. Nat. Mus., No. 37, p. 50, 1889. 



Axinus ferrtiginostts LOCARD, Curupagne du Caudan, Annales de 1'Universite de 

 Lyon, p. 191, 1896. 



This very common species was found at numerous stations from N. 

 lat. 42 47', W. long. 61 04', to K lat. 35 12' 10", W. long. 74 57' 15", 

 in 125 to 1,525 fathoms, 1880-1886. 



CRYPTODON (AXINULUS) OVATUS, new species. 

 (Plates XCI, fig. 7; XCIII, fig. 1.) 



Shell small, ovate, not swollen, with the posterior end produced and 

 somewhat pointed, rusty brown in color and heavily incrusted with 

 iron oxide, limbos rather flattened ; beaks small and concealed by the 

 coating of ferruginous matter. The anterior end is well-rounded with 

 a nearly semicircular curve; the ventral margin is broadly convex; 

 the posterior margin is tapered and produced at the end, with the 

 dorsal margin a little convex and sloping rapidly. The hinge-margin 

 is a little thickened and much obscured by the incrustation. In the 

 left valve there is a rather prominent, blunt, tooth-like swelling below 

 the lunular area; in the right valve there is a corresponding notch 

 and a rather wide ligamental furrow commencing beneath the beak, 

 and running back subparallel with the dorsal margin, becoming more 



