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observation;^ O'x a nuimber of 

 PLECTOPYLIS coi^iiECTKO IM tOi\h.I]V by 



m. IIANSUV ^IITH BESCRIPTIOX OF 



FOUR IVEIV SPEC'IES. 



By G. K. GuDE, F. Z. S. 



A small collection of Plectopylis from Tonkin, belon- 

 ging to the Scliool of Mines, Paris, bas been kindiy placed 

 in my hands by M. Dautzenberg. The shells were coUec- 

 ted by M. Maasuy, and are of inlerest, not only on 

 accouut of Ihe new species, but because of a considérable 

 séries of P. Giardi which bas enabled me to ascertain the 

 extent to which the armatures vary, several spécimens 

 exhibiting a curions combination of old and new barriers. 



Of the new species, two are allied to P. tennis, being, 

 like that species, somewhat abnormal members of the 

 section Sinicola and they still further tend to connecl 

 this section with the section Endoplon. 



One — P. soror — is of spécial interest, since it pré- 

 sents a feature I hâve not observed in any other species : 

 a curious curved ridge given ofï from the upper side of 

 the third palatal fold. 



Of interest also was the discovery in P. infralevis of an 

 insect behind the barriers, demonstrating that thèse mol- 

 luscs, in spite of their elaborate armatures, are not im- 

 mune from altacks by insects. Thèse structures, no doubt, 

 protect the animais from direct attack, but it is conceiv- 

 able that certain predatory créatures may oviposit be- 

 hind the barriers, and I was therefore not altogether sur- 

 prised on opening a spécimen of P. infralevis to find the 

 desiccated body of a minute insect. In endeavouring to 



