36 



DESCRIPTION OF A NEW SPECIES OF LIMN^A FROM 

 NORTH-WEST AUSTRALIA. 



By H. B. Pkkston. 



Read Sth December, 1905. 

 L1MN.EA. (BULINUS) EGBEGIA, D.sp. 



Shell sinistral, oblong ovate, somewhat solid, semi-transparent white ; 

 whorls 5, rapidly increasing, finely striated with lines of growth, the 

 last whorl rather inflated ; suture impressed ; umbilicus broad and 

 deep ; outer lip simple ; columella expanded below over the umbilical 



region and extending into a thick callosity, reaching to the junction 

 of the peristome with the whorl above. Alt. 11 '75, diam. maj. 6-5 mm. ; 

 aperture, alt. 6, diam. maj. 3 mm. 



Mab. — North-Western Australia. 



I was at first inclined to describe the above species as a Physa, but 

 Mr. B. B. Woodward having with his usual kindness worked out the 

 radula, and having carefully compared it with that of Physa and 

 Limncea^ I have now not the slightest doubt that it should be placed 

 in the former genus. This conclusion, I may sa}' , is also in accordance 

 with the views expressed on the Australian so-called Physoid forms 

 in a paper by Mr. A. H. Cooke. ^ 



Proc. Zool. Soc, 1889, pp. 136-143. 



