107 



67. Thalestris rufoviolacens, Claus. 



(PI. LXII). 

 Thalestris ruforiolacens, Claus, Die Copepodenfauna von Nizza, p. 33, PI. IV, tigs. 18 2^. 



Specific Characters. Female. Body comparatively short and stout, some- 

 what resembling in form that in T. longimana. Cephalic segment very large, 

 with the epimeral parts deep and greatly curved in the middle; rostral projection 

 somewhat prominent and acute at the tip. Urosome comparatively short, scarcely 

 attaining half the length of the anterior division, genital segment large and rather 

 broad in its anterior part; last segment, as usual, very small. Caudal rami ex- 

 tremely short, considerably broader than they are long, and densely clothed 

 at the end with delicate filaments, the 2 larger of the apical setse rather slender, 

 and issuing close together from a knob-like projection at the inner corner 

 below, outermost seta rather elongated and distant from the others. Anterior 

 antennae of the usual structure, 2nd joint rather large and tumid, terminal part 

 nearly half the length of the proximal part. Posterior maxillipeds of moderate 

 size, resembling those in T. giliba. First pair of legs likewise rather similar, 

 though with the inner ramus somewhat shorter than the outer. Last pair of legs 

 of quite extraordinary size, extending even beyond the 2nd caudal segment, both 

 joints broad, foliaceous, and ornamented on the surface with a peculiar, as it 

 were bipinnate marking; marginal seta? of both joints comparatively small and 

 simple. Ovisac small, rounded, and almost wholly concealed by the lamellae of 

 the last pair of legs. 



Male exhibiting the usual sexual differences from the female. 



Body of a whitish colour, variegated with irregular patches, partly of a 

 reddish, partly of a deep violaceous hue. 



Length of adult female 0.90 mm. 



Remarks. The above-described form is unquestionably identical with that 

 originally recorded by Claus as T. rufoviolacens. On the other hand the form so 

 named by Brady does not belong to this species, but apparently to the next. The 

 most characteristic features of the present form are the peculiar structure of the 

 caudal rami and the extraordinary size of the last pair of legs in the female. 



Occurrence. Only 2 or 3 specimens of this form have hitherto come 

 under my notice. They were taken, many years ago, at Her0, west coast of Nor- 

 way, in moderate depths among algse. 



Distribution. Mediterranean at Nice (Claus). 



