382 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



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

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

 It lacks the tine 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. Jonrn. 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 

 l^roduced, well rounded, thickened. Inner lip more thickened, with 

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

 Aiierture narrow posteriorly, ovate anteriorly. Surface smooth and 

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

 well-detiued, 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 i). nmhil- 

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

 OGCulta Mighels {=^ C. propinqua Sars). The latter is, however, destitute 

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

 surface is everywhere covered with distinct sijiral lines. Our shell is 

 shorter and stouter than D. umbilicata. 



Diaphana conulus (Desh.). 



UtricuhiH conulus G. O. Sars, op. cit., j). 287, pi. 17, figs. 17 a-c. 



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

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

 American coast. 



Amphisphyra globosa Loven, 1840. 



Diaphana (jloboaa G. O. Sars, op. cit., p. 290, pi. 18, figs. 3 c, 4 ; j)!. 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 pellucida (Brown) Lovdn, 1840. 



Diaphana ju 11 ncida Brown, 111. Recent Conch., pi. 19, figs. 10, 11, 1827. 

 Bulla hijalina Turton, Mag. Nat. Hist., vii, p. 353, 1834 {nou Gmelin). 

 Bulla deUUs Gonld, Invert. Mass., ed. i, p. 164, fig. 95, 1841. 

 Utriculufi hyalinus Jeifreys, Brit. Conch., iv, p. 427; v, pi. 94, fig. 7. 

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



(dentition). 

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



This species occurred at stations 870 and 894, in 120 and 365 fathoms. 



