88 A ■REVISION OF IHE BRITISH SPECIES OF 



species of Cyclops with eleven-jointed antennae, seeing that 

 the possession of that number of joints is characteristic of one 

 stage in the development of the seventeen -jointed forms. But 

 we have, in this case, the swimming feet all perfectly developed 

 and three-jointed, and no examples of any seventeen- jointed 

 forms were found in the gathering. For the present, therefore, 

 I must look upon C. Ewarti as being a good species. The figure 

 of the entire animal, given in the Fishery Board Report, is not 

 quite satisfactory, and I reget that I am unable here to give a 

 better one, no specimens having been preserved in a fit condition 

 for that purpose. 



16. Cyclops longicaudatus, Poggenpol (PI. X., figs. 5-7). 



1874. Cyclops longicaudatus, Poggenpol (26), p. 72, pi. XV., 

 figs. 19-21 ; pi. XVI., figs. 5-6. 



Female. — Body widest in front; tapering gradually and evenly 

 to the furca ; no distinct separation between thorax and abdo- 

 men. First cephalothoracic segment almost circular ; a distinct 

 constriction between it and the following segment, the sides 

 of which are somewhat produced backwards, forming angular 

 cusps ; third segment constricted in front, lateral margins protu- 

 berant, rounded, not at all angulated ; fourth segment somewhat 

 narrower, constricted in front, but produced behind so as to 

 form angulated, alseform lateral processes ; last thoracic scarcely 

 wider than the first abdominal segment, constricted in front, 

 lateral margins rounded ; first abdominal segment quite as long 

 as the following three, tapering backwards, constricted in front; 

 caudal rami about four times as long as broad ; equal in length 

 to the two preceding segments ; caudal setae short, delicately 

 plumose ; innermost of the two median setae more than half 

 as long as the abdomen, and only slightly longer than the next 

 (outer) seta ; bases of these two setse dilated ; the two secondary 

 apical setae are very short, the outer, however, distinctly longer 

 than the inner ; the lateral setae are situated at about the middle 

 of the outer margins of the rami and reach nearly to the apices. 

 The abdomen, altogether, including the furca, is more than 

 half as long as the cephalothorax. Anterior antennae eleven- 



