THE NAUTILUS. 55 



as a heritage from so early a fauna that the place of its origin and the 

 paths of its distribution will probably never he known with certainty. 

 There is a peculiar modification of Patula found only in New Zea- 

 land, to which Huttou has given the sectional name Tltera.^ New 

 Zealand has also received Paluloid snails from the Endodonta stock, 

 this group being a special dev^elopment of Patula confined to 

 Polynesia. The New Zealand niembei's of the subgenus Endodonta 

 belong to two groups of species, one of which contains P. cvyptobi- 

 dens, P. t'nnandra, P. Jessica ; to the other group Mr. Suter has 

 given the name Maorlana; these are minute discoidal forms hav- 

 ing numerous folds within the aperture. This group can only be con- 

 sidered a mere section of Endodonta, the species being closely 

 allied to minute forms o( Endodonta found in New Caledonia, etc. 



Another Helicoid genus represented by numerous species is 

 Laoma of Gray. This group is characterized by the small, thin, coni- 

 cal or depressed shell with thin simple lip. The jaw is composed of 

 numerous separate squarish plates, being very much like 

 that of our northern genus Punctum. The teeth also are peculiar ; 

 these composite jawed Helices are probably to be regarded as an 

 excessively ancient and primitive type but their affinities are Avith 

 Patula rather than with the so-called Gonlognatha. No species 

 known to belong to Laoma has been discovered outside of New Zea- 

 land. Hutton's genus Phrixgnathus must of course be united to 

 Laoma but the name may be retained as a section to contain species 

 without teeth in the aperture. 



A third genus of New Zealand Helices is also, as far as we now 

 know, confined to those Islands; this is the genus Gerontia of 

 Hutton. I use that name to comprise snails having the animal and 

 dentition of Patula except that the tail is provided with a mucus 

 gland. The jaw is thin and delicate and varies from striated to 

 ribbed. The shell is thin, somewhat translucent and its surface is 

 striated or ribbed, sometimes hairy or occasionally smooth. The 

 spire varies from low conical to nearly flat ; and it is a notable fact 

 which has hitherto escaped observation that whatever be the sculpt- 

 ure of the mature shell, the apical or embrvonic whorls are spirally 

 striated. This is an unusual feature and recalls to my mind that 

 strange Tasmanian Helix, Anoglypta launcedonensis. The snails 



1 The name Thera is already in u>e for a recognized genus of Geometric 

 moths, dating from 1831. As a substitute, Aesckrodomui may be used. This sec- 

 tion oi Patula includes H. alpha Pfr. and H. beta Pfr., the first being the tyie. 



