HORN EXPEDITION—MOLLUSCA. 
213 
with those of Isidom (Ehrenberg), included under Bulinus by H. and A. Adams, 
Gen. Moll., ii., p. 260, 1858. 
The first application of the name Isidora to an Australian species is by Tryon 
when describing Physa (Isidora) hainesi \n Amer. Jour. Conch., vol. i., p. 9, 1866 ; 
but the same author, in his Syst. Conchology, vol. iii., p. 103, places it as a 
synonym with Bulinus. 
The hgure of Physa neivcombi, in Reeves’ Icon. Conch., shows apparently a 
columella-fold. This is certainly an incorrect interpretation, as I have satisfied 
myself by an examination of the co-types received from the original collector, 
whereas it is really an exaggeration of an angulation produced by the retroversion 
of the peritreme on the body-whorl. 
Mr. Cooke has described (Quart. Journ. Conch., vol. v., pp. 241-243, pi. ii.) 
some of the anatomical characters of Physa inflaia.! Adams and Angas, from which 
lie concludes that because the dentition is similar to that of Linuiica the shell is a 
sinistral example in that genus, and names it L. physoides. He has however over¬ 
looked the fact that the tentacles are filiform-cylindrical, a character in association 
with a reversed spire, which should serve to maintain the species in the family 
Physidai. My observations on the external anatomy of P. inflata are that the 
tentacles are slender, suddenly dilated at the base of the upper outer side, the eyes 
on the inner base of the tentacles (see tig. 25, pi. xix.), the mantle not exsert with 
a plain margin. The animal of these Isidora-like shells, as observed by me in the 
species newconibi., inflala and brazieri, is thus related to Bulinus by its non- 
exserted and plain-margined mantle, but diflers from the rest of the family by its 
dentition, which allies it with Limnieidie. 
The animal of Isidora has not been described, and until its dentition has been 
diagnosed it will be unsafe to refer the Australian shells of the newcond>i-ty\)Q to 
it. On the assumption that the lingual ribbon will afford differential characters, 
I propose the name of Isidorella for the Australian shells. This course will 
be more convenient than the use of Isidora, in the belief that the anatomical 
characters are alike. 
List of IsiDORELLiE arranged chronologically. 
1863. — Physa neivconibi, A. Adams and Angas. 
Physa ferruginea, A. Adams and Angas. 
1864. — Physa inflata, A. Adams and Angas. 
1866.— Physa (Isidora) hainesii, Tryon. 
