133 



Colour yellowish. 



Length of adult female 0.50 mm. 



Remark*. The above-described form is unquestionably that originally 

 recorded by Glaus as Dactylopus flavus. Prof. Brady has confounded this species 

 with another very different form, to be described below as Idomene forficata 

 Philippi, only the female being referable to the present species, whereas the male 

 belongs to the Philippian species. 



Occurrence. I have only met with this form very occasionally, though 

 in several localities off both the south and west coasts of Norway. It occurs in 

 moderate depths, ranging from 6 to 20 fathoms, among algae and Hydroida. 



Distribution. British Isles (Brady), Mediterranean off Nice (Glaus). 



Gen. 35. IdOmene, Philippi, 1843. 



Generic Characters. Body pronouncedly depressed throughout, with the 

 anterior division broad and flattened. Cephalic segment rounded in front, without 

 any true rostrum. Urosome much narrower than the anterior division, though 

 distinctly depressed, last segment deeply cleft behind. Caudal rami produced, 

 divergent, inner apical seta spiniform. Eye absent. Anterior antennae in female 

 comparatively small, 6- or 7-articulate, in male much larger and very subchelate. 

 Posterior antennae with the outer ramus well developed, biarticulate. Mandibular 

 palp largely developed, with the basal part very broad, and both rami of unusual 

 sixe, the outer one armed outside with a number of strong falciform spines. 

 Maxillse and maxillipeds normal. 1st ^ir of legs with the basal part very broad 

 and flattened, both rami 3-articulate, the outer one shorter than the inner, and 

 armed outside with strong denticulated spines, inner ramus with the 1st joint 

 large and dilated, carrying inside a strong plumose setae, last joint armed at the 

 tip with 2 slender claws and a ciliated seta inside them. Natatory legs with the 

 rami nearly equal-sized; inner ramus of 2nd pair of legs in male only slightly 

 transformed. Last pair of legs not very large, distal joint armed outside with 

 strong spines. 



Remarks. This genus was established in the year 1843 by Philippi, to 

 include a small Copepod found by him in the Mediterranean at Naples. As only 

 a solitary specimen was observed, the exact structure of the appendages could of 

 course not be made out, and the detail-figures given merely represent some parts 



18 Crustacea. 



