188 Transactions. — Zoology. 



three is unknown. Amphidoxa rapida, said to come from New Zealand, 



occurs in North Australia (with a variety at the Solomon Islands) ; while 



Rhagada rienga, and Streptaxis taranaki, both doubtfully New Zealand, are 



closely aUied to species from the same place. Our closest connection thus 



appears to be N. Australia, but there is a considerable generic affinity with 



the faunas of New Caledonia, Polynesia, and S. America. 



Synopsis of the Families. 



Sec. GONIOGNATHA. 



Jaw of several transverse plates. 



Sec. HOLOGNATHA. 

 Jaw of a single piece. 



Sub-sec. Aulocognatha. 

 Marginal teeth quadrate, 



Fam. Helicidce. 

 Animal heliciform (except Otoconcha), the tail without a mucous gland. 



Fam. Charopidce. 

 Animal heliciform, the tail with a mucous gland. 



Sub-SeC OXYGNATHA. 



Marginal teeth aculeate. 



Fam. Vitrinida. 

 Animal heliciform, no caudal mucous gland. 



Fam. Limacidce. 

 Animal limaciform, no caudal mucous gland. 



Fam. ZonitidcB. 

 Animal heliciform, a caudal mucous gland. 



Sec. ELASMOGNATHA. 

 Jaw with a posterior accessory plate. 



Sec. AGNATHA. 

 No jaw ; teeth all aculeate. 



Fam. Streptaxidce. 

 Animal heliciform, no mucous gland. 



Fam. Testacellidm. 

 Animal limaciform, no mucous gland. 



As Pulmonate Mollusca are now always classified principally by the 

 structure of the animal and its dentition, it is not easy to make an analytical 

 key leaving out these important points ; but the following remarks may 

 assist collectors in naming their shells. 



1. Species with a few rapidly increasing whorls belong to Otoconcha, 

 Amphidoxa, Vitrina, Paryphanta, Elcea, Rhytida, or Daudebardia. 



2. Species with plaits inside the aperture belong to Tomatellina, Stro- 

 bila, Endodonta, Paxillus, or Diplommatina, 



