LNIO.— Plate XV. 



Ciiriousk bipnrtitc on the posterior side ; each part 

 beinn- smooth and convexlv swollen. 



Species (57. (Mus, Cuming.) 

 I'Nlo SACCULUS. Un. U'M subquadrato-ublotif/d, anlicc 

 declm-contractd, postici late ampUter expansd, ob- 

 scure radialim lineari-sulcatd, lidescente-oUvaced. 



The little bag Umo. Shell somewhat scpiarely ob. 

 long, anteriorly slopicgly contracted, posteriorly 

 broadly largely expanded, obscurely radiately li- 

 nearly grooved, yellowish-olive. 



Anthony, MS. iu Mus. Cuming. 



Hab. North America. 



This partakes somewhat of the character of the preced- 

 ing species, though not bipartite posteriorly. 



