ACANTHINULA. 189 



Euaca nth inula Westerlund, Fauna, i, 1889, p. 16. A. acu- 

 leata here designated type. 



Aulaca Westerlund, Rada Jugoslav. Akad., cli, 1902, p. 89. 

 A. aculeata here designated type. 



Shell turbinate, perforate or umbilieate, of few rapidly in- 

 creasing, rounded or subangular whorls. Initial iy 2 whorls 

 spirally striate, the rest with oblique riblets, much narrower 

 than the intervals, largely cuticular, each bearing a filament or 

 spine forming a crown above the periphery (sometimes want- 

 ing in the adult stage, and of course lacking in fossils) . Aper- 

 ture oblique, rounded-lunate, the lip with remote insertions, 

 thin, or thickened within and with a membranous expansion; 

 columellar margin dilated. 



Type: A. aculeata (Miiller). Distribution: western Palse- 

 arctic and eastern Ethiopian Regions. 



Palaeontology. — Acanthinula appeared near the base of the 

 Palasocene in forms somewhat intermediate in shape between 

 that genus and Zoogenetes. It was most abundant in species 

 in the Oligocene and Miocene, several of them resembling the 

 Canarian A. spinifera (Mouss.)). A. nana, with the sculp- 

 ture of Acanthinula, is in shape and size more like Punctum; 

 it appears to have left no descendants. A. tuchoricensis, the 

 only Tertiary species I have seen, has the embryonic whorls 

 spirally sculptured like the genotype, A. aculeata. Other Ter- 

 tiary species do not appear to have been specially examined 

 for this character. 



The following list of Tertiary species is compiled from 

 Wenz, Fossilium Catalogus, 1, Animalia, Part 20, iii (1923). 



Acanthinula archiaci (Boissy). Pupa archiaci Boissy, 

 Mem. Soc. Geol. France (2), iii, 1848, p. 275, pi. 5, f. 21.— 

 ? Acanthinula archiaci Wenz, Foss. Catal., iii, p. 969. Lower 

 Paleocene, Thanetien: Rilly -la-Montague near Reims. 



Acanthinula armoricensis (Cossmann). Helix stueri 

 Cossni., Bull. Soc. nat. Ouest France, v, 1895, p. 172, pi. 5, f. 

 16, 17 (not of Cossmann 1892). — Helix armoricensis (Oppen- 

 heim) Cossm., Bull. Soc. Sc. Nat. Ouest France (2), ii, 1902, 

 p. 115, pi. 11, f. 2. — Acanthinula a., Wenz, Foss. Cat., iii, p. 



