302 



with 3 strong spiniform setae. Ovisac oblong in form and rather large, extending 

 beyond the caudal rami, number of ova, however, rather limited. 



Male with the anterior antenna? transformed in exactly the same manner 

 as in the 2 preceding species. Last pair of legs somewhat imperfectly developed, 

 the distal joint not being defined at the base, and being only provided with 2 

 unequal setae; inner expansion of proximal joint very small, knob-like, with a spine 

 and a slender seta. 



Colour not yet ascertained. 



Length of adult female 0.52 mm. 



Remarks. This form is undoubtedly congeneric with the 2 preceding 

 species, from which it is at once distinguished, however, by the very long and 

 narrow caudal rami. It is also rather inferior in size. 



Occurrence. Only 2 specimens of this form, a female and a male, have 

 hitherto come under my notice. They were both found in a sample taken at Far- 

 sund, south coast of Norway, from a depth of about 20 fathoms, muddy sand. 





Gen. 63. RhlZOthrlX, Brady & Robertson, 1875. 



Syn: Erihydrosoma, Brady (not Boeck). 



Generic Characters. Body sub-cylindrical, smooth, with the segments less 

 sharply marked off from each other than in the preceding genera. Cephalic seg- 

 ment comparatively large, with the rostral projection obsolete. Caudal rami short 

 and broad. Anterior antennas with the number of joints much reduced and clothed 

 with partly ciliated setae. Posterior antennas with the outer ramus small, though 

 well defined. Mandibles strongly developed, with the masticatory part very coarse 

 and the palp distinctly biarticulate. Maxillae and maxillipeds of normal structure. 

 Natatory legs very small, but with long apical setae, inner ramus in all of them 

 biarticulate; 1st pair differing conspicuously from the others, apical setae of both 

 rami terminating in a tuft of delicate hairs. Last pair of legs with the inner 

 parts of the proximal joints coalesced. Ovisac single. 



Remarks. This genus was established in the year 1875 by Messrs. Brady 

 and Robertson, to include a species, R. curvata, found by them off the British 

 coast. In his Monograph, Prof. Brady withdrew this genus, believing it to be 

 identical with Enhydrosoma Boeck. On a closer examination, I have however felt 

 justified in restoring this genus, as the species upon which it was originally founded, 



