NO. 1139. BEEP-WATER MOLLUSC A VERRILL ANl> I'.rSTT. 811 



margin; external to tbis there are remnants of a small anterior liga- 

 ment occupying a short furrow. Commencing behind the beak and 

 extending to the base of the rostrum, there is a comparatively large 

 and prominent lamelliform process rising from beneath the margin and 

 projecting downward, with the face portion broadly rounded, and its 

 upper surface concave. Above the base of this, and extending from 

 near the beak to about the middle of the rostrum, is a narrow, slightly 

 thickened ridge separated from the dorsal margin by a narrow furrow. 



Length, 6 mm.; height, 4.5 mm.; breadth, about 3 mm. 



One valve, station 2055, among Foraininifera, X. lat. 27 22', W. long. 

 78 1' 30", in 338 fathoms, 1886. 



This species has considerable resemblance to H. clariculata Dall, but 

 the latter is more regularly ovate in form, and has a much shorter and 

 broader rostrum, and somewhat coarser sculpture. The posterior 

 shelf-like clavicle also differs in form, being quite narrow for a consider- 

 able distance next the cartilage-pit, and more expanded distally. The 

 shell described and figured by Smith 1 under the same name appears to 

 be a distinct species, and may be identical with our shell, for it has 

 nearly the same form and agrees closely in the narrow tapered rostrum. 

 The figure of the interior, however, in that case, is incorrect, owing to 

 the omission of the clavicle, and apparently the substitution of the hinge 

 of the left valve for the right. 



MYONERA GIGANTEA Verrill. 

 (Plate LXXVI, figs. 4, 5.) 



Necera glgantea VERRILL, Trans. Conn. Acad., VI, pp. 223, 277, 1884; Expl. Alba- 

 tross, Report U. S. Com. Fish and Fisheries for 1883, p. 574, 1885. 



Three imperfect, dead specimens have been found at three stations 

 between N. lat. 38 22', W. long. 70 IT 30", and N. lat. 37 56' 20", 

 W. long. 70 5V 30", in 1,825 to 1,917 fathoms, 1883 and 1886. 



MYONERA RUGINOSA (Jeffreys) Verrill and Bush. 

 (Plates LXXII, fig. 4; LXXIV, fig. 2.) 



Near a ri<</in<>x JEFFREYS, Proc. Zool. Soc. London, p. 042, pi. LXXI, fig. 7, Novem- 

 ber, 1881. SMITH, E. A., Report Voy. Challenger, Zool. Lamellibranchiata, 

 XIII, p. 35, 1885. 



Shell small, short, broad-ovate, not much swollen, with a short, wide, 

 gaping, obliquely truncate rostrum. Umbos small, prominent, not much 

 swollen; beaks small, prominent, incurved, smooth -and shining. The 

 anterior portion is evenly rounded, nearly semicircular; the antero- 

 dorsal margin is convex and prominent; the ventral margin is broadly 

 and evenly rounded, except at the base of the rostrum where it is sin- 

 uous and incurved; the postero-dorsal margin is nearly straight to the 



1 Report Voy.Challenger Zool. Lamellibranchiata, XIII, p. 52, pi. ix, figs. 8-8&, 1885. 



