HYALEID^. 91 



and rugose ; dorsal surface longitudinally ribbed ; lateral mar- 

 gins rectilinear. 3 sp. Miocene ; northern Italy. 



POCULiNA, Bellardi, ISll. Surface not transversely undulated ; 

 lateral margins slightly convex. 3 sp. Miocene ; northern Italy. 



EucHiLOTHECA, Fischcr, 1882. 



Distr. — Cleodoi^a Parisie7isis,Desh.. Eocene; Paris. 



Shell narrow, conically subulate, apex subinflated, ovoid, 

 mucronate, not septate within ; aperture ovate, horizontal, not 

 oblique, margin externally reflected, sometimes bilabiate. 



Hyalocylix, Fol., 1875. 



Distr. — H. ( Gleodora) striata, Rang. Mediterranean, Atlantic. 



Shell conic, slightly depressed, transversely grooved ; aperture 

 oval, not oblique ; summit acuminated. Animal with bilobed 

 wings. 



Styliola, Lesueur, 1826. 



Syn. — Creseis, Rang, 1828. 



Distr. — 6 sp. S. subulata, Quoy (xlii, 6). 



Slender, conical, pointed, straight, or curved. Fins rather 

 narrow, truncate, with small tentacles projecting from their 

 dorsar edges, and rudiments of the mesopodium on their surface ; 

 mantle-margin with a spiral process on the left side. M. Rang 

 states that he has seen these pteropods clustering round floating 

 seaweed. 



Mr. Arthur Adams has observed them, during a calm in the 

 Atlantic towards the decline of day, shining near the surface 

 like myriads of glassy spicula ; the}^ often remain posed and 

 motionless, and their progression through the water is verj'- 

 irregular. 



Barrande has seen a triangular operculum in connection with 

 H. striatus, as well as similar bodies with other species. 



CuviERiA, Rang, 1827. 



Dedicated to Baron Cuvier. 



Distr. — 4 sp. Atlantic, India, Australia. G. columella, Rang 

 (xlii, 9). Fossil, 4 sp. Miocene and Pliocene ; Turin, Calabria. 



Shell cylindrical, transparent ; aperture simple, transversely 

 ovate; apex acute in the young, afterwards partitioned ofi", and 

 usuallj^ deciduous, so that the end of the shell is blunt or 

 truncate. 



Animal with simple narrow fins, united ventrally by two small 

 lobes ; lingual teeth I'l-l. 



VAGiNELLA, Daud, 1802. Shell oblong, with a pointed apex ; 

 aperture contracted, transverse. Fossil, 4 sp. Miocene ; Bor- 

 deaux, Turin. G. depressa, Daud (xlii, 32). 



The genus Triptera, Quoy and Gaimard, 1824, was founded 

 on a fragment of a Cuvieria. 



