66 SUTKR : DESCRIPTION OF A NEW SPECIES OF SEPARATISTA. 



The unique specimen is most likely not quite adult, and therefore 

 has the last whorl but very little disunited. The genus iSeparatista is 

 new to the tauna of New Zealand. The species is nearly allied to 

 aS'. separafi^fa, Dillw., and perhaps S. grayi, Ad., but may at once be 

 distinguished by the beautiful and complicated sculpture. 



Hedley'^' suggests that " Trlcliotropis (/abrieli, F. and G., 1\ (jrazi- 

 lenta, Braz., and T. foirularis, T. AVoods, may conveniently be 

 distinguished from the typical northern Trkhotropi^i, and assembled 

 under Scparafisfa." I fully shar^i Mr. Hedley's opinion with regard 

 to the forms mentioned by him, but there is one stumbling block in 

 the way as far as New Zealand is concerned, and this is Tricliotropis 

 inarndfa, Hutton { = rlafhrata, Sow.). If Tricliotropis is an exclu- 

 sively northern genus, the question arises : What is inornata ? It is 

 quite true that the membranaceous fringes of 2'ricliofro[)is are wanting, 

 but otherwise the shell has all the characters of that genus, and I 

 cannot make up my mind to class it under iSeparafiafa. The species 

 of the latter genus seem to be exceedingly variable, but to include our 

 T. inornata would necessitate retorming Gray's diagnosis of Separatista 

 to such an extent, that it would almost become a synonym of Tricho- 

 tropis. So far as I can ascertain, the operculum and the animal of 

 Separatida are unknown, and the same is the case with T. inornata, 

 so that with the little knowledge that we possess at the present time 

 we have to admit the occurrence of Tridiotropis not only in the 

 northern, but also in the southern hemisphere. It is represented by 

 about seven species in Japan, and there seems to be no reason why it 

 should not also be found in New Zealand. 



