44 MARGUERITE HENRY. 



This form was present in abundance in a collection made 

 &t Botany in July. 



This species was collected at Nagpur in India, and in 

 Australia from the Gracemere and Crescent Lagoons near 

 Rockhampton. 



Oyprinotus fuscus, sp. n. 

 (Plate II, figs. 13, 14). 

 The carapace of the adult female attains a length of 2 mm. 

 so that this form grows to a larger size than the other 

 Australian species. 



Viewed laterally, the carapace exhibits a wide oval shape, 

 with the greatest height 1*3 mm. occurring about the 

 middle. The anterior extremity is obliquely rounded and 

 somewhat narrower than the posterior. The dorsal margin 

 forms a bold, fairly regular curve; the ventral margin is 

 slightly convex and joins the anterior and posterior ex- 

 tremities without any intervening angle. Seen from above 

 the carapace is rather tumid; the anterior extremity is 

 more pointed than the posterior. The valves are unequal, 

 the left one slightly overlaps the right at both ends, but 

 dorsally and ventrally it is surpassed by fairly large pro- 

 jections of the right valve. The ventral edge of the left 

 valve has a very slight ventral sinus, but the projection of 

 the right gives a convex appearance to the lateral view of 

 the carapace. The left valve has a smooth edge through- 

 out, but the right one, as in all other species belonging to 

 the genus, has a series of small tubercles inside the anterior 

 and posterior extremities. These give the edge a minutely 

 crenulated appearance. 



The surface of the carapace is smooth and polished ; it 

 is marked with the usual scattered pits. There are only a 

 few hairs, and these are confined to the extremities. 



