382 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



It is a small, very smooth, white shell, in form closely resembling 

 young specimens of Cyliclina alha, for which it may easily be mistaken. 

 It lacks the fine spiral lines usually seen on the latter, and is rather 

 more narrowed posteriorly. The apex of the spire is occupied by a shal- 

 low depression, and there is no umbilicus. 



Diaphana gemma Verrill. 



Amer. Jouru. Sci., xx, p. 399, Nov., 1880. 



Shell oblong, suboval, widest a little in front of the middle, truncate 

 posteriorly and obliquely rounded anteriorly, with a distinct umbilicus, 

 and also with a narrow, deep pit at the apex. Texture of shell rather 

 solid, somewhat thickened. Outer lip rising somewhat above the spire, 

 forming a rounded posterior angle ; throughout most of its length only 

 slightly convex, often nearly straight ; anteriorly, a little expanded and 

 produced, well rounded, thickened. Inner lip more thickened, with 

 the edge a little revolute, but leaving a small and regular umbilicus. 

 Aperture narrow posteriorly, ovate anteriorly. Surface smooth and 

 glossy, without any sculpture over the middle region, but with several 

 well-defined, not crowded, but fine spiral grooves at each end, visible 

 with a lens. Color grayish white. Length, 4.2"""; breadth, 2.5'""'. 



Stations 871 and 873, 100 to 115 fathoms, fine sand, south of Martha's 

 Vineyard and Newport, E. I. 



I have had no opportunity to examine the animal of this species, and 

 refer it to Diaphana, provisionally, because of its resemblance to D. umhil- 

 icata. It may prove to be a Cylichna. It has some resemblance to C. 

 occulta Mighels (= C. propinqiia Sars). The latter is, however, destitute 

 both of the pit at the summit of the spire and of the umbilicus, and its 

 surface is everywhere covered with distinct spiral»lines. Our shell is 

 shorter and stouter than D. unibilicata. 



Diaphana conulus (Desli.). 



Ufriculus conulus G. O. Sars, op. cit., p. 287, pi. 17, figs. 17 a-c. 



A perfect living specimen of this very distinct species was taken at 

 station 870, in 155 fathoms. It has not been recorded hitherto from the 

 American coast. 



AmpMsphyra globosa Lr,v6ii, 1846. 



DiapJuina glohosa G. O. Sars, op. cit., p. 290, pi. 18, figs. 3c, 4; pi. xi, fig. 12 

 (dentition). 



Specimens agreeing in all respects with Sars's figures, referred to 

 above, were dredged at stations 870, 871, and 894, in 115 to 365 fathoms, 

 south of Martha's Vineyard and Newport. 



Amphisphyra psllucida (Brown) Lov^n, 1846. 



Diaphana X)dluc\da Brown, 111. Recent Conch., pi. 19, figs. 10, 11, 1827. 

 Bulla h'yaUna Turton, Mag. Nat. Hist., vii, p. 3.33, 1834 {-non Gmelin). 

 Bulla dehilis Gonkl, Invert. Mass., ed. i, p. 164, fig. 95, 1841. 

 Utricitlus hyaUnus Jfeftreys, Brit. Conch., iv, j». 427 ; v, pi. 94, fig. 7. 

 Diaphana hyalina G. O. Sars, op. cit., p. 289, pi. 18, figs. 1 a, h; pi. xi, fig. 10 



(dentition). 

 Diaphana dchiUs Gould, Invert. Mass., ed. ii, p. 216, fig. 507. 



This species occurred at stations 87C and 894, in 120 and 365 fathoms. 



