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182 RALPH TATE. 
elliptic ; outer lip thin, arched medially ; peritreme incomplete ; 
columella with a fold-like twist, medially sulcated. Length 13, 
breadth 4:5 mm.  Localities—Eocene: Muddy Creek; Spring 
Creek, Geelong (an uncertain identification. 
Genus Jsapis, H. and A. Adams. 
The fossil which I refer to this genus has the general aspect of 
Isapis fenestratus, Carp., as illustrated in Tryon’s Man. Conch., 
Vol. 1x., p. 273, t. 52, f. 11, but it possesses a revolving plait on 
the columella ; whereas that genus is described as having a small 
median tooth on the columella, Mayer says of Raulinia alligata 
in establishing the genus, ‘‘sa columelle non tordue, aplatie, et 
qui porte 4 lintérieur, une dent tuberculeuse independante pour 
ainsi dire, et qui n’a absolutement rien a faire avec le pli des 
Odontostoma.” Specimens of Raulinia alligata, Desh., from the 
Middle Oligocene of Pierrefitte, which I owe to the generosity of 
M. Cossmann, all exhibit a revolving plait on the columella, and 
if the so-called tooth of Lsapzs proves to be a plait, then the only 
distinction between the two genera is that Jsapis is umbilicated 
and Raulinia imperforate. A second species, having the facies of 
the other, hasa closed umbilicus; I cannot call one Jsapis and the 
other Rauwlinia, as I think the presence or absence of an umbilicus 
is a character too unstable for generic distinction. If I am right 
in my conjecture as to the presence of a plait in J/sapis asin 
Raulinia, then the latter must merge into the former ; if I am 
wrong, then the two species here described must belong to Raulinia 
and its characters amended in respect of the umbilicus and embryo, 
as also by the substitution of a “revolving plait” for a “ tooth” 
on the columella. The heterostrophe pullus of Zsapis eothinos, mihi, 
places it in Pyramellide, whilst the slightly arched and concave 
columella brings it in the neighbourhood of Yossarus ; Lacunodon, 
Cossmann, among Littorinide, is closely simulated by it. 
IsAPIs EOTHINOS, spec. nov., Pl. x., fig. 11. 
(Raulinia eothinos, Tate, MS.) 
Shell oval-oblong, test thin, apex obtuse, embryo obtuse with 
a looped tip. Whorls five, rapidly increasing, convex though 
