122 " PK. G. STEWARDSON BRADY ON" [May 17, 



similar to what one would expect in ordinaiy ISToitliern collections. 

 With the exception of one species, for which I have thought it 

 best to propose a new generic name — Ectocyclops — all are i-efei- 

 able to familiar European genei'a. 



Cyclops leuckarti Glaus. 



Tliis appears to be less plentiful in the Natal gathei-ings than 

 any of the following species, though more conspicuous owing to its 

 greater size. 



The form described by me years ago under the specific name 

 scourjleldi* has been identified by other authors (Lilljeborg, 

 Herrick, Schmeil) with C. leuckao-ti Claus. I am doubtful as to 

 the correctness of this identification. Both »Schmeil t and 

 Herrick J figure, with differences, peculiar pellucid marginal 

 laminfe on the last two joints of the larger antennae. I have 

 been unable to detect any such structure in my British specimens 

 of C. scourfieldi, neither does it exist in the Natal specimens nor 

 in others from Ceylon which I refer to the same species. And it 

 may be noted that Lilljeborg, while accepting Schmeil's description 

 and figures as belonging to G. letickarti, does not himself i-efer in 

 his definition to these antennal laminae. Herrick, on the other 

 hand, figures and describes them, and expresses a doubt as to the 

 identity of the species with C. scourfieldi. I do not myself 

 possess authentic specimens of C. leuckarti, and must be content 

 for the present to leave the question in suspense. 



Cyclops pusillus, n. sp. (Plate YI. figs. 11-18.) 



Female. Body slender, tapering gradually from before back- 

 wards (fig. 11); thoracic segments not produced at the angles, 

 except the last which is exti'emely short and angulated : abdomen 

 very slender, the fii'st segment nearly as long as the united lengths 

 of the following three segments ; furcal segments slender, scarcely 

 longer than the pi-eceding abdominal segment ; principal tail-seta 

 neai'ly as long as the whole abdomen. Ovisacs closely adpi-essed 

 to the abdomen and containing only a few comparatively large 

 eggs. Antennules twelve-jointed, slender, somewhat longer than 

 the entire cephalothorax, bearing numerous long setse (fig. 12). 

 All the branches of the first four pairs of feet three- jointed ; 

 spines of the first pair (fig. 17) veiy slender and setiform ; fifth 

 pair (fig. 18) rudimentary, almost obsolete, consisting of a minute 

 papilla from which arise two vmequal setee. Length, exclusive of 

 tail-setje, 0-46 mm. 



This is the smallest species of Cyclops with which I am 

 acquainted. But its general dcA^elopment and the fact of many 

 specimens bearing ova, indicate that it is not an immatui-e foi-m. 



* Brady, G. S. " A Revision of the British Species of Freshwater Cyclopidse and 

 Calanidse" (Nat. Hist. Trans. Northumberland & Durham, vol. xi., 1891). 



t Schmeil, Deutschlands freilebende Siisswasser-Copepoden. 1 Tail, Cyclopidse. 

 1892. 



% Herrickj Synopsis of the Entomostraca of Minnesota, 1895. 



