216 RETU8A. 



is rarely mamillate or scalariform. This form is common in the 

 iterranean. Alt. 1-1 J, diam. $-:{ mill. 



K. PKBTENUU Mighels. PI. 23, figs. 48, 49. 



Shell small, thin, translucent whitish or light brown, cylindrical, 

 the spire very low-convex ; whorls 3$, the first somewhat turned in- 

 ward ; sutures deeply impressed ; last whorl descending, sculptured 

 with irregular, light, arcuate growth-stria?. Aperture narrow above^ 

 dilated below; outer lip strongly arched forward and bent slightlv 

 inward in the middle ; columella thickened but not plicate. 



Alt. 3-2, diam. 1-8 mill. 



Mnn.tfu-husetla Bay ; Fernandina, Fla.; Coast of JA/ /'///; Green- 

 Ion <l \ Xorway. 



Bullaperteniil* MKJIIELS, Bost. Journ. Nat. Hist, ii, p. 346, pi. 

 16, f. ZUtriculiis pertenuis GOULD (\V. G.B.edit.) p.218, fig. 509. 

 SARS, Moll. Reg. Arct. Norv. p. 287, pi. 17, f. 19. AD., Th. -s. 

 Conch, ii, p. 371, pi. 120, f. 19. SOWB., Conch. Icon. f. 4. DAM.. 

 Blake Gastr., p. 45 ; Cat. Mar. Moll. S.-E. U. S., p. 86. AURIYII.- 

 i.ir>, Vega-Exped. Vetenskap. Arbeten iv, p. 371. 1) /'/////<///</ per- 

 tenuis VERRILL, Amer. Journ. Sci. (3), xx, p. 399. 



This species has been united with 7^. obtusaand R. semenby many 

 authors, but the three are here retained distinct because proof of 

 their complete intergradation is still lacking. R. obtusa seems to 

 be a more solid, larger shell, replacing perk-n //'. in English and 

 .-oiitlH-rn European waters; B. semen \8 a somewhat shorter form 

 from lii^'h latitudes. 



I; -i MEN Reeve. PL 23, figs. 55, 56, 57. 



Shell cylindrical-ovate, rather tumid, the spiiv dopivssrd convex, 

 - mm- impressed; whorls smooth, slightly convex, the last a little 

 descending in front ; tawny-white. Of a short cylindrical form, 

 somewhat swollon, with a depressly convex spiiv, having the suture 

 faintly channelled, i /.' 



Port Refuge ; Nova Zemblin. 



Alt. ',, diam. 3| mill. (Leche). 



Alt. 4), diam. 3 mill. (Leche"). 



Bulla semen Ildcher's Last of the Arctic Voyages, ii. p. 



:. \<i-c, 1855. Utriculas semen LECHE, Kongl. Sv. 

 Akad. Ilandlin-ar. \vi. IK.. '2, p. 71, 1878, (with v. / -Itnujnta). 



I. che describes a f.rm with higher spire as Var. efonyitn. It 

 i- not the game a* /'. //////// Moll. 



