2 GARRETT: ON POLYNESIAN MITRID.E. 



water-worn stones in the middle region of the httoral zone, on 

 rocky coasts usually associated with Neritce. 



Every species enumerated in the following list were collected 

 by the writer, so that the habitats, station and geographical rangs 

 may be relied on as trustworthy. 



Further exploration will I am sure add many more species 

 to the list and modify the geographical range of others. 



In addition to the 167 species collected by myself, I have 

 added 29 species on the authority of other authors. 



The Polynesian shells which have been described under the 

 name of Thala, a subgenus of Mitridiv, are much more nearly 

 related to Pleurotomidce than with the former family, and with the 

 exception of Thala alba and T. sallata, which are true Miirce, I 

 have excluded the others from this catalogue. 



The structure of the folds or wrinkles on the columella are 

 not true plaits, but simply more or less irregular transverse 

 rugosities precisely of the same structure as observed in certain 

 species of Clathiirella and Cithara. 



In fact the earliest known species was described by Dr. 

 Mighels, under the name of Pleiiroioina todilla. Mr. Reeve in 

 his Monograph of Mangelia has described a Philippine species 

 under the name of Mangelia solida. The latter is exactly the 

 same shape, and the granulate sculpture, linear aperture and the 

 columellar wrinkles do not differ from Polyntsian species. 



The above two species, together with Thala a?igiostoma Pease, 

 and T. exquisita and violacea Garr., should be embraced in a new 

 genus and removed to the family Pleuroiomidre. 



I also exclude from the Mitridcz Mr. Pease's genus Mitropsis, 

 which undoubtedly belongs to the family Columhellidce. 



