214 RETUSA. 



R. SDBSTRIATA Jeffreys. Unfigured. 



Shell represented by a single specimen, which was unfortunately 

 broken in sifting the dredged material. It resembles Bulla hyemalis 

 Couthouy (=Amphisphyra globosa Loven, Utriculopsis vitrea M. 

 Sars) except in being smaller, shorter, and equally broad through- 

 out, instead of barrel-shaped ; the crown is consequently longer in 

 proportion and not so much raised at the point ; but the especial 

 difference consists in this being beautifully sculptured, and not 

 smooth like the other species ; besides a few coarse spiral ridges the 

 whole surface is closely and microscopically striated in the same 

 direction. Length (M, breadth 0'075 in. (Jeffr.}. 



North Atlantic, 1750 fins. 



Utriculus substriatus JEFFR., Ann Mag. N. H. (4), xix, p. 334. 



UTRICULUS OBESUS Jeffreys, Rep. Brit. Ass. Adv. Sci. 1880, p. 387. 

 Bay of Biscay (name only). 



UTRICULUS PUSILLUS Jeffreys, I. c. Same locality (name only). 

 UTRICULUS EXCAVATUS Jeffreys, /. c. Same locality (name only). 



R. OBTUSA Montagu. PL 23, fig. 51. 



Shell forming an oblong cylinder, constricted in the middle, and 

 becoming broader towards the base ; it is usually opaque, and rather 

 glossy : sculpture, numerous slight lines of growth ; and in young 

 and fresh shells may be somtimes detected under the microscope 

 extremely close-set and fine wavy spiral lines; spire indistinctly 

 striated across ; epidermis skin-like, cream-colour passing into 

 brownish-yellow ; colour white ; spire short, but very variable in 

 that respect, being in some cases almost truncated, while in others 

 it is more or less extended ; whorls 4, slightly angulated at the top ; 

 those in the middle gradually enlarge; the apical or central whorl 

 is globular and turned inwards ; suture deep and narrowly excav- 

 ated ; mouth flexuous, upper half narrow ; lower half wide, with a 

 rounded base ; outer lip gently curved, never extending to the apex ; 

 it recedes above, so as to leave a space between the outermost whorl 

 and the next, and is contracted and inflected in the middle : outer 

 corner rounded ; inner corner obliquely incurved ; inner lip thicker 

 than in the last species, continuous with the outer lip above ; it is 

 reflected over the pillar, behind which it occasionally forms a small 



