MARINE MOLLUSCA OF THE UNITED STATES. 103 



pressed, imperforate ; surface reticulated by fine microscopic 

 striae ; lip arising from the margin of the circular pit at the sum- 

 mit of the spire ; aperture linear above, broad below ; umbilicus 

 covered with enamel, which gradually disappears within the aper- 

 ture ; white under a ferruginous epidermis. 



Length 1.5, diam. 2.5 mill. 



New England, northwards. {Eur.) 



2. C. oryza, Totten. Fig. 209. 



{Bulla.) Am. Journ. Sci., xxviii. 350, t. 5. 1835. 



Shell minute, not very thin ; tip depressed into a shallow pit, 

 and base rather acute ; aperture as long as the shell, narrow above 

 and wider below ; outer lip sharp, regularly arched rising a little 

 higher than the shoulder ; an oblique, truncated fold on the colu- 

 mella ; white. 



Length 1.5, diam. 2.5 mill. 



New England, south of Cape Cod. (Eur.) 



According to Mr. Jeffreys this shell r= B. utriculus, Brocchi, 

 1814. 



Genus UTRICULUS, Brown. 

 Brit. Conch. 1844. 



Head disk very short ; tentacular lobes lateral, rounded ; eyes 

 none. 



1. U. Gouldii, Couthouy. Fig. 210, 211. 



(Bulla.) Bost. Journ. Nat. Hist., ii. 181, t. 4, f. 8. 1839. 

 U. turritus, Moller, Ind. Moll. Grcenl. 1842. 

 Bulla pertenuis, Mighels, Proc. Bost. Soc, i. 129. 1843. 



Shell thin, small, of four whorls, rounded at their upper edges, 

 with well-defined sutures and fine transverse striae; spire de- 

 pressed, discoidal, sometimes slightly mammillated; no umbilicus ; 

 white, with yellowish epidermis. 



Length 7.5, diam. 2.5 mill. 



New England. (Eur.) 



The Bulla jiertenuis of Mighels (Fig. 211) appears to be the 



young of Gouldii. 



2. U. canaliculatus, Say. Fig. 212. 



(Volvaria.) Journ. Philad. Acad., v. 211. 1826. 

 Bulla obstricta, Gould, Am. Journ. Sci., xxxviii. 196. 1840. 



Shell minute, cylindrical, polished, with very faint lines of 

 growth ; spire convex, a little elevated, with minute but promi- 

 nent tip ; whorls about five, with their shoulders very obtusely 



