igiS.] H. H. Godwin-Austen : Mollusca, VIII. 591 



vertical; peristome thin; columellar margin nearly vertical, then 

 suddenly oblique, not reflected. 



Size: major diam. 15*0 mm. (specimen dissected and also of 

 typical spirit specimen). 

 ,, 12-8 mm. (No. 5999, 7-i-i2, small). 



Mr. Kemp thus describes the living animal. 



" Gastropod C" 7 — 9-i-i2. "Shell with upper part of each 

 " whorl flattened. Underleaf-stemsof plantain, very scarce. Shell, 

 " when animal is extended, beautifully marbled, owing to the 

 '■ body-colouring showing through. For the most part black with 

 ''large flecks of pale buff and maroon, some of the flecks on the 

 ''inner whorl having a yellowish tinge. Anterior part of the 

 " animal of a colour similar to B (described as Sarama kempt G.-A. ), 

 " with similar arrangement of granules, but the ground colour is 

 " greyish and not so pale as in that species. Kye-stalks dark grey 

 " with a bluish tone. Mantle lobes dark rich sepia closely flecked 

 "with pale buff. Hind part of foot much flattened, square in 

 " section ; beneath the shell pale with minute orange-brown flecks. 

 " Further bfxck the colouring is a curious mixture of orange-brown 

 " flecks and dull dark purple. In general effect the hind-body is 

 " dull purple with pale dull orange, brown in the median line and 

 " a tinge of the same colour at the sides. Under surface of foot 

 " dull maroon, greyish in front and more crimson behind. Dorso- 

 " lateral margin of the sole of the same colour as the sole with in 

 " addition very minute white flecks ; a dark grey dividing line be- 

 " tween this marghi and the upper part of the bod3^" 



This is certainly the most interesting species discovered by 

 Mr. Kemp in the Abox Hills, both as regards the animal and the 

 shell, and it is the type of a new genus. I name this species in 

 honour and in memory of Mr. Noel Williamson of the Indian Civil 

 Service, who lost his life (30th March, 1911) penetrating into wilds 

 of the Abor country, keen on their exploration and the desire of 

 getting on friendly relations with the tribesmen. Williamson 

 had already distinguished himself as a pioneer on the frontier 

 in this way further to the East on the Lohit or Zellu River to- 

 wards Rema in 1907-08, when he made a good plane table survey 

 of the country, and wrote an interesting account published in the 

 "Geographical Journal," Octr. 1909. I was in correspondence 

 with but never had the pleasure of meeting him. His murder led 

 to the expedition up the Tsanspu, to the subjection of the Abors, 

 and the accurate mapping by the officers of the Indian Survey of a 

 vast area of unknown country in this part of the Eastern Himalaya, 

 while the zoological collections have proved of extraordinary value 

 and interest. I have named the new genus " Rokmgia" after 

 the village in which it was found, also because the men of Rotung 

 had a large share with the men of Kebang in the massacre of the 

 Civil Officer and all the party. 



Animal : foot elongate, narrow when extended, with an indis- 

 tinct central area on the sole. A long overhanging or curved 



