93 



THE EADULA IN SOME MITEIDiB. 



By Lieut.-Col. A. J. Peile. 



Read 7th, April, 1922. 



The radula of the Mitridae formed the subject of a paper by the 

 Rev. Dr. A. H. Cooke in Proc. Zool. Soc, 1919, pp. 405 to 422. The 

 object of the present note is principally to put on record the form of 

 the radula in a few additional species. I have to thank the officials 

 of the British Museum (Natural History) for permission to study the 

 collections in their charge and refer to the same in this paper. 



1. Mttra. 



M. soUda, Reeve. Two specimens from Twofold Bay, New South 

 Wales, kindly provided by Mr. T. Iredale from his Roy Bell Collec- 

 tion, furnished radulaB having 64 and 61 rows respectively. Number 

 of cusps on rhachidian 9. Number of cusps on laterals : 13 and 14 

 in one specimen, 15 and 16 in the other. (Fig. 1.) 



ilf ./wsca, Swainson. Madeira. A specimen in the British Museum 

 Collection agrees fairly well with the figure in Troschel. 





2. Vexillum. 



F. costellaris, Lamarck. A specimen from Singapore, in the 

 Gwatkin Collection (not recorded by Cooke), has 47 rows plus 

 nascent. Rhachidian is bow-shaped with 15 cusps and is peculiar 

 in that the centre cusp is smaller than the rest, which diminish 

 slightly outwards. Lateral rather blunt. (Fig. 2.) 



