280 DIAl'HANA. 



Aperture narrow, dilated in front ; inner lip straight, truncated be- 

 low ; outer lip produced behind, rounded (Ad.}. 



Mino-Simti, Jnjian, H3 fms. 



Roxanl'i jnuu-tiilain An., Ann. Mag. N. H. (3), ix, p. 158. 



No species hitherto described resembles this ; the nearest approach 

 to it is R. crane hit Leach. R. inscnlpta Totten is sculptured rather 

 like it. The shell is solid, very strongly punctate-striate, ami 

 deeply umbilicated, and the inner lip is truncate anteriorly (Ad.). 



Genus DIAPHANA Brown, 1837. 



Diapluma BROWN, Conchologist's Text Book, 4th edit., p. 98 

 (type D. Candida Brown = Retusa minuta Brown, 1827). 8AB8, 

 Moll. Reg. Arct. Norv. p. 288. Ampliisphyra LOVEN Ofversigt 

 Kongl. Vet. Akad. Forhandl. 1846, p. 142 (A.globow Lov. and .1. 

 pellucida Brown). Utrim/tts (in part) of BROWN, JEFFREYS, Sow- 

 ERBY, et al. Physema H. & A. Ad., Gen. Rec. Moll, ii, p. 21, type 

 D. hiema/is. 



Shell thin and fragile, capacious or subglobose, umbilicated, the 

 spire either projecting, flat, or sunken in a narrow apical umbilicus. 

 Aperture narrowed above, rounded below, the lip sinuous; coin- 

 mella not thickened, long and rather straight, neither folded nor 

 truncated, its edge a little reflexed above. Type D.minuta Brown. 



Animal (pi. 61, fig. 22, D. expansa) capable of being contained 

 in the shell ; frontal disc small, produced in two conical processes 

 at the anterior angles ; eyes present or wanting ; epipodial lobes 

 apparently wanting ; foot auriculate at the anterior angles, split 

 into two triangular tails behind. No stomach plates. 



Radula short, with the formula 1.1.1. Central teeth are delicate, 

 erect, oblong laminae, with bilobed and closely serrate upper mar- 

 gins ; laterals are large and falcate, the long, rather straight, obtuse 

 cusps crossing above the centrals ; iim-iui wanting (pi. 61, figs. 20, 

 21, J>. Huniit'i). 



I >Utribution, mainly North Atlantic. 



Capt. Brown seems to have included the species of this genus at 

 first in Retu*a, then in Dinphana, and finally in I'tr'n-nln*. I have 

 n.it seen the first edition of the " Conchologist's Text Book," issued 

 in 1 *.",:;, and do not know whether ]>i>ij,hn; t 'i was published at that 

 tiiiM- or not. It appear-, properly defined, in the fourth edition, 

 1837; but in 1844 Brown places the species under I'tr'u-uln* as a 



