ENTOMOSTRACA FROM CEYLON. 335 



nnmarkefl. These faint markinp-s wei'e shown in my drawing 

 and have become accentuated in the plate. 



Macrotiirix odiosa Gurney. 



Peradenija pond. Abundant in a plankton collection taken 

 at night, but much less common in plankton and in weeds during 

 tlie day. Also taken at Anuradhpura. 



The species bears some resemblance to M. singalensis, but 

 differs from it in the form of the upper lip, the arrangement 

 of cilia, and teeth on the antenna and on the post-abdomen. 

 While the adult differs considerably from M. triserialis in the 

 shape of the valves, the young closely resemble it, being of a 

 pointed pear-shaped form. 



Macrothrix triserialis Brady. 



Mahintele — Snake's pool. Two specimens only seen, 



Leydigia australis Sars. 



In a tank at Anuradhpura greab numbers of cast shells of a 

 species of Leyiigla were taken, and among these there are two 

 or three post-abdomina, but none with the terminal claw 

 attached. However, the shape of the post-abdomen and the 

 ari-angement of the spines, together with the fact that the shell- 

 valves are not striated, make it certain that the species is 

 L. austrcdis. The arrangement of the spines is distinctive 

 in this species; there is a regular series, decreasing in size 

 anteriorly, of groups containing one long spine and two very 

 short ones, and these groujDS are not replaced by groups of cilia 

 till the anal depression is reached. 



At Mahintele a single specimen of a Leydigia was taken which 

 a,grees most closely with L. australis var. ceylonica Daday. In 

 this specimen the spines of the post-abdomen are more slender 

 and pnrtly arranged in fours (PI. I. fig. 1), and the shape of the 

 post-abdomen recalls that of L, 'propinqtia. My specimen, which 

 is much decayed, differs from Daday 's form in absence of sculptui-e 

 on the shell. 



Alona rectangula Sars. 



A few specimens of a small form of this species were taken in 

 Pei'adeniya pond. Some females are ephippial, but no males 

 were seen. In some specimens the upper lip has a minute tooth 

 on its anterior margin. 



Alona intermedia Sars. 

 Old tank at Anuradhpura. 



Alonella davidi Richard. 



One specimen and a moulted shell were included in a collection 

 from the old tank at Anuradhpura. They agree exactly with 

 regard to form of post-abdomen and ari'angement of spines and 



