1910.] FRESHWATER CRUSTACEA FROM THE TRANSVAAL. 151 



hairs. However, it has not been without some hesitation that 

 they have all been placed in the genus Cypris. Miiller gives 

 as characteristic for this genus, that the third biting process 

 of the maxillula has two claw- like bristles distinct from the others 

 which may or may not be toothed (p. 51). This is so in the 

 cases of Cypris gunningi, C. ch?Hssiensis, and C. inastigophora, 

 and possibly of C. tubercvlata ; but although the maxillula of 

 G. spinosa possesses these toothed bristles, it has, in addition, 

 two small ones of similar character. It was not considered 

 expedient to create another genus for this species on that 

 character and others mentioned below, nor yet a new sub-genus, 

 so it has been placed temporarily in the genus Cypris. 



As to the common relationship of these five species, it will 

 be seen that whereas G. gunningi and C. chrissiensis are closely 

 connected one with the other, G. spinosa and C. tuber culata are 

 aberrant, chiefly in the characters of the shell and of the maxillula. 

 C. mastigophora undoubtedly conforms in many particulars to 

 the subgenus Cypridopsis. 



Besides the new species, Cypris venu&ta (Vavra, loc. cit.) was 

 found fairly plentifully in Lake Chrissie ; the most notable 

 feature of this Cyprid is the presence of peculiar marginal 

 denticulations on the shell. 



Genus Cypris O. F. Miiller. 



Cypris spinosa, sp. n. (Plates VIII. , IX. & X. figs. 9-12.) 



Length 3*3 mm. ; breadth 2 - 52 mm. ; height 2*05 mm. 



External appearance : from the dorsal aspect, the shape of the 

 body is roughly quadrilateral, the ventral margins of the shell 

 being expanded horizontally into wings. From the dorsal posterior 

 region of each shell spring two long stout spines directed 

 backwards. The anterior dorsal border of each valve is 

 furnished with eight small spines ; between the fourth and 

 last spines are regular groups of bristles. The lateral expanded 

 wings of the valves are much flattened and are produced along 

 their posterior border into four or five spine-like processes ; on 

 the rounded surface of each shell there are two small prominences 

 present. 



The general colour is mottled umber ; specimens found in 

 Lake Chrissie were greenish. 



Appendages. — The eight-jointed antennule resembles that of 

 a typical Cypris. 



The antenna consists of four joints : the second joint is 

 furnished with five long swimming-hairs which reach to the 

 end of the claws ; the claws are longer than the terminal 

 segments ; just behind the claws are found three fine bristles. 

 The second joint is provided dorsally and ventrally with rows 

 of small fine hairs which vary somewhat in size and arrangement. 



The mandible resembles very closely that of Eimjcypris pubera 

 as described by Claus (1). 



