On Fresh-water Crustacea. By Robert Gurney. 289 



described by others. In rny specimens the ephippium resembles 

 exactly that of some forms of C. quadranyida. The ampullar}' 

 area is covered with small, rather protuberant reticulations, each 

 with a minute chitinous knob in the centre. The remainder of 

 the ephippium dorsal to the ring of air cells is strongly reticulate, 

 with a small rod of chitin projecting from the centre of each mesh. 

 These rods are very conspicuous along the dorsal margin. Grada- 

 tions can be traced from the condition in the ampuliary area, where 

 there is but a minute knob to the condition with well-developed 

 rods. The male does not differ from that of C. dubia. 



The importance to be attached to the structure of the ephippium 

 as a specific character is uncertain. In C. quadranyida, while it 

 is generally spiny, it may also have the normal form. Also 

 Stingelin (1895) has met with one example of a spiny ephippium 

 in C. pulchella Sars, so that it appears that this form of shell orna- 

 ment is not constant, and therefore not of specific importance. 



There are two other points of difference between my speci- 

 mens and C. dubia. Firstly, my specimens are very large, some 

 measuring as much as 1 • 5 mm. in length ; and secondly, the adult 

 female carries eggs varying in number from five to eighteen. Both 

 these differences are, however, quite unimportant in comparison 

 with the identity of structure, and are due to the occurrence of 

 the animal in small pools rich in food, instead of in large open 

 waters. The length of the dorsal abdominal process is probably 

 also connected with the larger number of eggs in the brood-pouch. 



Moina salinarum sp. n. — Head depressed, the dorsal margin 

 with a slight depression behind the eye (plate X. fig. 13). Frontal 

 angle rather sharp ; ventral margin of the head nearly straight. 

 Valves of the shell without any sculpture, fringed with setae 

 along their ventral margin, and with the posterior margin some- 

 what sinuate. Eye small, its diameter about one-fourth of the 

 length of the head. First antenna? short and comparatively thick, 

 one-seventh of the whole length of the body (plate X. fig. 14). 

 Anterior seta inserted nearly in the middle of the antenna, and 

 rather more than one-third of the length of the latter. Posterior 

 margin of the antenna fringed with exceedingly delicate cilia, which 

 are not easy to see. Sensory rods very short. Second pair of 

 antennae stout, the rami shorter than the stem. 



Post-abdomen less than half the length of the body, and rather 

 slender. The post-anal part very short, less than one-fourth of the 

 length of the whole post-abdomen. Terminal claws short and stout, 

 the cilia along their edge somewhat stronger at the base, but not 

 forming a comb (plate X. fig. 15). Lateral teeth 10 to 12 in 

 number. Dorsal edge of the pre-anal part covered with delicate 

 cilia, which here and there take an arrangement in transverse rows. 



Length 1-35 to 1*8 mm. 



Male and ephippial female unknown. , 



June 16th, 1909 x 



