432 Lt.-Col. IT. II. Godwin-Austen on 



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

 flume quite simple and spineless. 



Etadula : form of teeth as in E. leucostyla ; 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 dcpressedly globose, others orbiculately de- 

 pressed, with strong ribbing ; this assemblage has con- 

 sequently been placed in different genera from the coneho- 

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

 isolation on oceanic islands of small area, under conditions 

 only varying with altitude, has evidently l< j d 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 propose the 

 name " Ereptinae." 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 

 Didida2 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- 

 ji.sittaevs (a large parrot) and a Xycticoraz fa 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 EsEPTiyj:. 



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. Radula and jaw as in the family Zonitidse. 



In a consignment of Mauritian shells collected by 

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



