154 THE HON. PAUL A. METHUEN OX [Feb. 1, 



The maxillula : the forward -directed palp bears six fairly long 

 bristles, two of which are plumose and one short. The distal 

 joint bears three large and three small bristles, besides a number 

 of hairs set close behind the base of the bristles, and one stout 

 hair on the inner margin. The third biting process is peculiar. 

 Besides the normal foliaceous setae and bristles characteristic 

 of the genus, the process is provided with a short seta which 

 is armed with a number of hairs springing from its distal 

 extremity and set at right angles to this seta : close but external 

 to this structure is another seta considerably larger and thicker 

 whence spring several short bristles. The other two biting 

 processes, which are without the foliaceous structures found in 

 C. spinosa, bear a number of stout smooth bristles. 



The maxilla : the exopoclite has fourteen plumose hairs as 

 against thirteen present in C. spinosa ; the plumose median 

 seta of the endopodite is very long. The male accessory 

 copulatory processes are, on the whole, stout ; the distal joint 

 of each differs considerably, one being slender, the other 

 pear-shaped. 



The fourth post-oral appendage : the third segment distinctly 

 consists of two pieces ; two rows of minute bristles border the 

 distal margin of the fourth and fifth segments ; the arrange- 

 ment of the terminal setae of the fourth segment differs from 

 that found in C. spinosa. 



The fifth post-oral appendage : the median seta of the third 

 segment is longer than in C. spinosa ; otherwise similar. 



The caudal furca : the rami are generally stouter than in 

 C. spi?iosa ; clistally a double row of serrations are borne along 

 half their lengths ; the two large distal processes on each ramus 

 are relatively stout and short. 



Locality. Found abundantly in littoral water of Lake Chrissie. 



Cypris chrissiensis, sp. n. (PI. XL fig. 16 ; PI. XIV. figs. 34, 

 35 ; PI. XV. fig. 37.) 



Length '73 mm.; height *44 mm. External appearance: in 

 proportion to its depth this species is not so long as C. gunningi, 

 the ratio of length to depth being as L7 : 1 ; correlated with 

 this comparative decrease in length or increase in depth are two 

 factors, namely, that the convexity of the dorsal surface of the 

 body and a concavity in the ventral margins of the shell are 

 more evident. In nearly all other respects this species resembles 

 C. gunningi. It also bears a great resemblance to Cyprinotus 

 congener (Vavra, loc. cit.), especially in the character of the accessory 

 copulatory processes of the maxilla?, The general shape of the 

 body and of the gnathobase of the mandible, and the structure of 

 the accessory maxillary copulatory organs, are sufficient evidence 

 that this is not a young form of C. gunningi ; further, more 

 than one female Was found with rijDe ova and introduced 

 spermatophores. which leaves no doubt on the subject. 



