122 AMERICAN MARINE CONCHOLOGY. 



six, last large, with a very obscure keel ; axis umbilicated, keeled 

 on the edge. 



Diam. 10 mill. 



Arctic Seas. 



Genus SPIRIALIS, Eydouxand Souleyet. 

 Rev. Zool., 235. 1840. 



1. S. GOULDII, Stimpson. Fig. 254. 



Proc. Bost. Soc. Nat. Hist., iv. 8. 1851. 



Heterofusus balea, Binney (not Holler), Gould's Invert., edit. ii. 505. 1870. 

 Shell ovate-globose, vitreous, very thin, pellucid, very light, 

 narrowly and deeply umbilicated ; spire conoid ; whorls seven, 

 sculptured by minute, distant, unimpressed, revolving lines ; last 

 whorl large ; aperture about equalling the spire, obtuse in front. 



Length 2.5, breadth 1.8 mill. 



Massachusetts Bay. 



2. S. ALEXANDRA Yerrill. Fig. 255. 



Am. Journ. Sci., 3d ser. iii. 281. 1872. 

 Heterofusus retroversus, Binney (not Fleming), Gould's Invert., edit. ii. 



505. 1870. 

 Spirialis Flemingii? A. Agassiz (not Forbes), Bost. Proc., x. 14. 1865. 



Body-whorl very ventricose ; spire of four whorls, not forming 



half the length of the shell. 



Nahant, Mass. 



Family CLIONID JB, Gray. 

 Syn. Brit. Mus. 1840. 



Genus CLIONE, Pallas. 

 Spicil Zool., x. 28. 1774. 



1. C. LIMAOINA, Phipps. Fig. 256. 



{Clio.) Voyt North Pole, 195. 1774. 

 Clio borealis, Brug. Encyc. Meth. Vers., i. 506. 1792. 



Gelatinous, pellucid, pale-blue ; mouth and end of the body 

 scarlet when out of water, hyaline ; wings somewhat triangular ; 

 tail acute. 



Portland, Me., northwards. 



CLASS ACEPHALA. 



Animal without head, always aquatic, contained within a bi- 

 valve-shell, one valve of which is applied to the right and the 

 other to the left side of the body. 



