73 



relative size of this zone is of specific walue taken in conjunction 

 with cognate characters ; aperture grooved posteriorly, and truncate 

 and deeply sinuous in front. 



Ancilla may bo distinguished from Olivancillaria, with which it 

 is frequently confounded, in that the latter, sensu stricto, has the 

 columella callous thi-oughout its entire length, the spire is usually 

 much more acuminate, and the sutures are deeply canaliculate. 

 The columella of the section Agaronia, however, is not callous, 

 except to a feeble extent posteriorly. Ancilla is readily dis- 

 tinguished from that subgenus, as the latter has such well- 

 developed sutures, and the comparative absence of callosity on 

 the spire and body-whoii is well marked. 



The subgenus Sparella, almost universally adopted by modern 

 authors, must disappear in synonymy, for the following reasons : — 

 The type of Ancilla is A. cinnamomea, Lamarck, and the type 

 of Sparella is A. alhisuleala, Sby. ; but these two species are 

 synonymous with each other, the only distinguishing feature 

 between them being that the impressed groove of the latter is 

 white — a character without constancy. It is generally stated 

 that a more or less prominent denticle on the outer margin of the 

 aperture characterizes Sparella, but that is found also in the type 

 species of Ancilla ; the spread of the callosity over the spire is 

 usually regarded as a special feature, but what value that may 

 possess from a morphological point of view does not in any way 

 affect the synonymity of the type species mentioned. 



Ti/pe. — Ancilla cinnamomea, Lamarck. 



Ancilla pseudaustralis, Tate (sp.). 



1889. AnciUaria pseudaustralis, Tate, Trans. Eoy. Soc. South Aust. vol. xi. 



p. 148, pi. vi. fig. 13; pi. vii. fig. 1. 

 1893. Ancillaria pseudaustralis, Tate and Dennant, id. vol. svii. pt. 1, 



p. 220. 



This is the largest Australian Ancilla in the Museum. Professor 

 Tate compares it with the European Eocene A. luccinoides, Lamk., 

 but it differs markedly from the latter : the broad band trespassing 

 anteriorly on the smooth zone of the body- whorl, terminating at 

 the inner margin of the aperture by a pronounced denticle forming 

 a slight postei'ior prolongation of the band, or of the groove which 

 borders it posteriorly, at once distinguishes this species from 



