tEARSONlA. l2;i 



Plerovyclus {Spiraculum) nevilli, Nevill, Hand List, i, 1878, p. 264. 

 rearsonia {Pearsonia) nevilli, Kobelt, Das Tierreich, Lief. 16, 1902, 



p. 174. 

 Pearsonia nevilli, Kobelt, Concli.-Cal)., Cyclophoridae, ii, 1911, 



p. 765, pi. 112, figs. 1, 2. 



Orvjinal description : — " Shell discoidal, couvexly depressed, 

 widely unibilicated, coAered with a dark brown epidermis which 

 soon becomes eroded, and with an incipient dark band on the keel 

 in perfect ;!.pecimen«. Spire very slightly raised, suture deep, 

 whorls 5, much rounded, the last descending slightly towards 

 the aperture. The sutural tube is only O-lO" [2*5 mm.] in 

 length, 0-3" [7'5 mm.] behind the aperture, turns back, and 

 is situated close to the suture. Aperture oblique, circular. 

 Pei'istoriie double, inner lip continuous, having at the suture a re- 

 entering angular notch, the outer is siuiilarly notched and then 

 expanded and folded into a spout-shaped form. Operculum not 

 seen, probably as in aS'. hispidum. 



" Alt. 0'36 [9 mm.], major diam. I'Oo [26"5 mm.], minor diam. 

 0-92r23-5 mm.], apert. 0-45 in. [11-5 mm.]."' 



Hah. India : Dihiri Parbat, Dalia Hills, Assam {Godwin- Austen). 



"This S'/nracidum is quite distinct from ^S'. liispidum, for which 

 I mistook it when found, and consequently omitted to search for 

 more examples. In the form of the sutural tube it most nearly 

 resembles aS'. avanum W. Blf., thus differing v^ery considerablj' 

 from *S'. liispidum^ in which that part is broad and curves quite 

 over and across the suture in well-grown shells. The most not- 

 able point of difference, however, is the expansion of the outer lip 

 into a tube-like process, in which respect the species shews its very 

 close alhnity to the genus Fteroci/clos." {Godwin- Austen.) 



Pearsonia nevilli, G.-A., var. 



Spiraculum nevilli, var. (iodwin-Austen, Itec. lud. Mas. viii, 

 1915, p. 497. 



" Shell very openly umbilicated, discoid. Sculpture, close spiral 

 liration, accentuated at tlie u)iddle half of the whorl looking at it 

 from above. Colour dark madder-brown, mottled or rather 

 streaked closely with ochre bands which, as they approach the 

 apex, are closely zig-zagged, beneath plain. A distinct black 

 band on the periphery. Spire very flat. Suture impressed. 

 Whorls 5, regidarly increasing. Aperture circular, oblique. 

 Peristouie double, thickened, much reflected, expanding forward 

 near suture into a spout-like shape, which continues as a raised, 

 pronounced narrow ridge on the reflected whorl, the epidermis 

 being peculiarly shining. A little further development would 

 constilute this a tube, such is its appearance. Operculum multi- 

 spiral, about 10 whorls, the edges slightly raised and furred on 

 outer martiin." 



