54 



[No. 8. 



and obtuse, dorsal margin greatly arcuate, almost angular in the 

 middle, ventral nearly straight: seen from above very tumid, almost 

 globular, greatest width behind the middle and about equalling 

 4 /5 of the length, anterior extremity narrowed, posterior broadly 

 rounded. Surface of shell rather hairy and everywhere 

 closely set with small depressed pits, marginal part of anterior 

 extremity with distant transverse grooves, posterior edge of left 

 valve armed with a series of very small tuberculiform denticles. 

 Colour light yellowish green, with 3 irregular flexuous dark 

 green transverse bands, the two anterior confluent above; 

 marginal part of anterior extremity very dark, almost black, 

 with a light- coloured border. Length of adult female 0,70 mm. 



Remarks. — The present species is easily distinguished from 

 the northern form, C. vidua Miiller, with which it rather agrees 

 in colour, by the much higher and more globular shell, as also by 

 its distinctly granular surface. The Australian species, G. minna 

 (King), has, according to the description and figure given by 

 Brady a still higher shell and moreover differs in colour from 

 the present form. The 2nd Australian species described by 

 Brady, C. funebris, has been based only upon quite young speci- 

 mens which had not yet assumed any definitive form, and hence it 

 is impossible to recognise the species. The two Ceylon species, 

 described by the same author, are both, I believe, different 

 from the one here described. 



Description. — The length of the shell in adult specimens 

 does not exceed 0,70 mm, and hence this species is somewhat 

 smaller than the northern form, C. vidua. 



Seen laterally (PI, II, fig. 9 ) the shell exhibits a very short 

 and high, rounded triangular form, with the greatest height 

 exactly in the middle and somewhat exceeding 2 / 3 of the length- 

 The anterior extremity is rather broad and obliquely rounded, 

 the posterior somewhat lower and obtuse. The dorsal margin 

 is exceedingly arched, almost angular in the middle, and slopes 

 rather steeply both anteriorly and posteriorly. The ventral 

 margin is very short, nearly straight and well defined from the 

 anterior edges. Seen from above (fig. 10) the shell appeal 



