432 Lt.-Col H. H. Godwin-Austen on 



was attached to a very long, finely pointed^ and narrow 

 flume quite simple and spineless. 



lladula : form oi: teeth as in E. leucostyJa ; formula : 



25 . 1 . 10 . 1 . 10 . 1 . 25, or 3G . 1 . 36. 

 Jaw slightly curved, with a central projection. 



The internal anatomy of these eight species shows a most 

 interesting similarity of type, while their shells differ in a 

 remarkable way. We have them with large solid shells of 

 turbinate or depressedly turbinate shape, some small, thin, 

 smooth, and depressedly globose, others orbiculately de- 

 pressed, with strong ribbing ; this assemblage has con- 

 sequently been placed in different genera from the concho- 

 logist's point of view, which need not be altered. Long 

 isolation on oceanic islands of small area, under conditions 

 only varying Avith altitude, has evidently led to the greatest 

 variation taking place in one direction only, viz. the shell. 

 Association with all other genera being cut off, changes in 

 the animal could only be specific and slight. 



I consider this Mascarene group of land-mollusca is well 

 worthy of subfamily distinction, for which I proj)Ose the 

 name "Ereptinpe.'^ Similar anatomical detail has not been 

 met with by me in any of the Indian genera, nor as yet 

 in any South African I have examined. The distinction 

 bears out the extremely isolated position of these islands 

 and their great antiquity — islands where such a family as the 

 Didid?e was developed ; where so many rare and now extinct 

 genera lived, such as the flightless rails Aphanapteryx of 

 Mauritius and Erythromachus of Rodriguez, with Lopho- 

 psittacus (a large parrot) and a Nycticorax (a night heron) 

 respectively ; where the reptilia and plants all point to 

 extremely long isolation following on a once far more 

 extended range and connection with lands of distant 

 geological age. 



Subfamily Ereptinjs, 



Shells of very varied form ; animal with no shell-lobes. 

 Foot divided, with mucous pore, peripodial grooves, and 

 border. Genitalia : no amatorial organ ; penis with 

 lengthened flagellum and long spermatheca ; the spermato- 

 phore without spines ; a capsule attached to a long tapering 

 flume. Kadula and jaw as in the family Zonitidae. 



In a consignment of Mauritian shells collected by 

 Monsieur E. Dupont and sent to me by Mr. John Ponsonby 



