358 On Oie genus Pompholyx and its Allies, 



Tandon, and Grav, who figure them as continuous. The great- 

 est care and experience in observation is required to make reli- 

 able notea on the dentition. 



Limneria, II. & A. Adams, belongs to the Othudce. 



( 1 hoanomphtUu8 i Geretfeldt, in the present state of our knowl- 

 edge, cannot be positively placed ; but, if not a Trqpidina, is 

 closely allied to Pompholyx and Carinifex. 



Brondelia, Bonrg., from its peculiar habitat, the impressed 

 radiation- and rounded ribs of the shell, as well as the polished 

 periostraca, differs, in my opinion, sufficiently from the Ancyli 

 to take rank as a genus. The type, which is from Algerian 

 forests, is figured by Binney, L. and F. W. Shells of N. A., 

 Part II., p. 146. 



It is with great hesitation that I have followed Menke and 

 Troschel in separating the Ancylidm as a family. The differ- 

 ence in the mode of coition seems to be chiefly mechanical, 

 caused by the form of the shell. This patelloid shape is the 



Btrongest character. 



On the other hand, the form of the foot, the jaws, and den- 

 tition agree closely with the typical LimnceidcB. At any rate. 

 the characters which separate them are tar less valuable than 



those which distinguish the Physidw from the LimnaidcB. 



The Bub-family Camptocerina Beems necessary, from the 

 very distincl characters which separate it from the other 

 groups. I feel justified in separating it provisionally until 



more is known. 



No one who has read the account of the growth of Ound- 

 /</,/,;,/, by Dr. Stimpson (in Proc. B.8. X. II. 1863), can have 

 much doubl thai the genua Poeyia i Bourg., is a young Gtmd- 

 lachia, and there i- much probability that Ancylus Cvmi/nr 

 gianu8, of the Bame author, from Tasmania, is an immature 

 Latia. There i- a possibility thai the latter genus (if the posi 

 tion of tin- eyea be correctly reported) may belong to the group, 

 characterized by a rudimentary operculum, of which Navicellix 



