358 KEY. A. M. NORMAX AND ME. G. S. BRADY 



names, longirostris and lo-ngi spina, believing that these at any 

 rate must be regarded as species ; and yet it has not been with- 

 out much hesitation that we have ventured to consider them dis- 

 tinct from each other. 



2. Bosmina longispina, Leydig. PL XXII, figs. 1, 2. 



1850. (?) Bosmina longirostris, Baird. British Entomostraca, p. 

 105. PL XY, fig. 3. 



1860. Bosmina longispina, Leydig. Xaturges. der Daphniden, 



p. 207. PL YIII, fig. 62. 



1861. Bosmina oltusirostris, G. 0. Sars. Om de i Omegnen af 



Christi. forekom. Cladocerer, p. 11. 



Head depressed, tumid above, being elevated on the crown, 

 rostrum short, obtuse ; anterior antennae of moderate length, 

 nearly straight, neither much curved nor bent downwards. Pos- 

 tero-ventral angles of carapace produced downwards into large 

 and elongated spine-like processes ; the lower margin of which 

 is sometimes notched in one or two places. Surface of shell 

 everywhere striated, the striae being very evident on the sides of 

 the head ; antero -ventral portion reticulated. Superior margin 

 of abdomen mostly about eight times crenulated towards the pos- 

 terior extremity, and bearing one or two minute curved setae ; 

 supero-posteal angle mostly acute. Abdominal claws having six 

 to eight small spines on the edge, which increase in length from 

 before backwards. Length, 4 A 3 -rd to -grrth of an inch. 



The figure in the Natural History of the British Entomostraca 

 seems, from the length of the infero-posteal produced angles of 

 the valves, to be intended to represent this form rather than that 

 last described. Among the specimens collected at the Humbles, 

 we found numerous males. These are smaller, and longer in 

 proportion to their breadth than the females ; the rostrum is 

 blunter, and the anterior antennas, which are longer and more 

 slender than the same organs in the female, are distinctly arti- 

 culated to it ; the first feet are furnished with a large, hook- 

 shaped process, the extremity of which is blunt ; and the abdomen 



