oliyid-e:. 33 



mens named O. irisans in the late Mr. Gaskoin's collection 

 because they have a callous spire, are only varieties of Olira 

 tremulina ; indeed some of the specimens which have not a cal- 

 lous spire are placed with them, under the name of irisans. 



It is therefore evident that the character which has been 

 regarded as of sectional or even generic importance, is not of 

 permanent specific value in certain species, while it appears 

 to be permanent and even one of the generic marks of other 

 groups. 



Tribe II. ANCILLARINA. 



Shell subcylindrieal, polished; suture of spire callous. Mantle 

 without any posterior beard. Lateral teeth of the tongue simple, 

 curved. Shell more or less covered with an enamel coat ; outer 

 lip often with a tooth in front, leaving an impressed groove on 

 the outer surface of the front of the last whorl. 



In the late Mr. Gaskoin's collection there were two specimens 

 of a large ovate fusiform shell, from Albany in South Africa, 

 which are arranged with Ancilla ; but the spire is not callous, 

 with a simple suture. It is probably arranged with this genus 

 because it possesses an anterior sunken groove caused by a labial 

 tooth ; but this tooth and groove are found in several other 

 genera, as Chorus, Concholepas, Acanthiza, Gastridia, Latirus, 

 Murex, &c. 



* Sliell partly covered with enamel. 



Genus 12. ANCILLA. 



Spire covered with an enamel coat, forming a narrow belt on 

 the penultimate whorl, not reaching to the hinder part of the 

 mouth, and leaving a naked space on the whorl ; axis perforated ; 

 outer lip with a tooth in front. Operculum large, distinct, oblong, 

 acute ; nucleus subapical, near the front of the inner side. 



I have only observed the operculum in A. obtusa and A. 

 australis. 



f Spire distinct. 



1. Ancixla CINGULATA. B.M. 



Ancillaria cingulata, Soiv. Spec. Conch. Ancill. 6. f. 36, 37. 



Kiener, Ancill. 10. t. 4. f. 1, 1. 

 Hah. China (Kiener). 



The apex rounded and rather large ; the callous sutural 

 band with a raised margin. 



