CLASS GASTROPODA 
Family SPIRATELLIDAE 
Genus SPIRATELLA Blainville, 1817 
Coquille papyracee, tres-fragile, planorbique, subcarenee, enroulee un 
peu obliquement, de maniere a etre profondement et largcment ombiliquee 
d’un cote; spire un peu saillante, et pointue de l’autre; ouverture grande, 
entiere, non modifiee, elargie a droite et a gauche; le peristome trenchant. 
(Blainville.) 
Shell subglobose, sinistrally spiral, umbilicated; whorls transversely 
striated; umbilicus margined. (Tryon, Structural and Systematic Con - 
etiology.) 
Type. Spiratella antarctica Forbes. 
Distribution. Arctic and Antarctic seas, gregarious. 
Spiratella pacifica Dali, 1871 
American Journal of Conchology, 7:138. 
Shell with a band of brown following the suture, especially the last, 
umbilicus small. This I have also compared with Atlantic specimens; the 
shell is more depressed, has a larger number of whorls, is smaller, with 
a narrow umbilicus. (Dali.) 
Type in United States National Museum. Type locality, Monterey, 
California. 
Range. Point Barrow, Arctic Ocean, to Monterey, California. 
Family CAVOLINIIDAE 
Genus CAVOLINA Abildgaard, 1791 or 1783 
Shell globular, translucent; dorsal plate rather flat, produced into a 
hood; aperture contracted, with a slit on each side; posterior extremity 
tridentate. (Tryon, Structural and Systematic Conchology .) 
Type. Hyalea tridentata. 
Distribution. Atlantic, Mediterranean, Indian Ocean. Fossil: Mio¬ 
cene—Sicily; Turin; Dax, Azores. 
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