HYALEID. 91 
and rugose ; dorsal surface longitudinally ribbed ; lateral mar- 
gins rectilinear. 3 sp. Miocene; northern Italy. 
POcULINA, Bellardi, 1871. Surface not transversely undulated ; 
lateral margins slightly convex. 3 sp. Miocene; northern Italy. 
EucuiLoruHeca, Fischer, 1882. 
Distr.—Cleodora Parisiensis, Desh. Eocene; Paris. 
Shell narrow, conically subulate, apex subinflated, ovoid, 
mucronate, not septate within; aperture ovate, horizontal, not 
oblique, margin externally reflected, sometimes bilabiate. 
Hyatocyrix, Fol., 1875. 
’ Distr.—H. ( Cleodora) striata, Rang. Mediterranean, Atlantic. 
Shell conic, slightly depressed, transversely grooved ; aperture 
oval, not oblique; summit acuminated. Animal with bilobed 
wings. 
Strytriota, Lesueur, 1826. 
Syn.—Creseis, Rang, 1828. 
Distr.—6 sp. 8S. subulata, Quoy (xlii, 6). 
Slender, conical, pointed, straight, or curved. Fins rather 
narrow, truncate, with small tentacles projecting from their 
dorsal 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; they often remain posed and 
motionless, and their progression through the water is very 
irregular. 
Barrande has seen a triangular operculum in connection with 
Hf. striatus, as well as similar bodies with other species. 
CuvieriA, Rang, 1827. 
Dedicated to Baron Cuvier. 
Distr.—4 sp. Atlantic, India, Australia. C. 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 off, and 
usually 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 1-1-1. 
VAGINELLA, Daud, 1802. Shell oblong, with a pointed apex ; 
aperture contracted, transverse. Fossil, 4 sp. Miocene; Bor- 
deaux, Turin. (. depressa, Daud (xlii, 32). 
The genus Triptera, Quoy and Gaimard, 1824, was founded 
on a fragment of a Cuvieria. 
