52 



of outer edge apparently wanting. Anterior antennae comparatively short and 

 stout, not nearly attaining the length of the cephalic segment, and gradually 

 attenuated distally; 2nd joint much the largest, 4th joint about half the length 

 of the 3rd; terminal part somewhat shorter than the 2 preceding joints com- 

 bined. Posterior antennae and oral parts of quite normal appearance. 1st 

 pair of legs resembling somewhat in structure those in /. furcata; 2nd joint 

 of inner ramus however comparatively shorter, not attaining the length of the 

 1st; apical claws of this ramus considerably longer than in /. furcata. Natatory 

 legs of the usual structure. Last pair of legs of moderate size, with the distal 

 joint oblong oval in form and comparatively broader than in I. furcata, edges 

 of the joint only provided with a few scattered small spinules, apical setae 

 rather slender. 



Colour of the living animal not yet ascertained. 



Length of adult female 0.62 mm. 



Remarks. The above-described form may be easily recognised by its 

 wery short and compact body, and more particularly by the unusually poor 

 development of the urosome. It belongs to the smaller species of the pre- 

 sent genus. 



Occurrence. Two female specimens only of this form have as yet 

 come under my notice. They were found in a sample taken, some years ago, 

 at Riser from a depth of about 50 fathoms. 



Gen. Idyella, G. O. Sars. 

 41. Idyella major, G. O. Sars, n. sp. 



(PI. XXXIII, fig. 1). 



Specific Characters. Female. Body rather short and stout, with the 

 anterior division considerably dilated and somewhat vaulted dorsally. Cephalic 

 segment very large, about as long as it is broad, and evenly rounded in front; 

 rostral projection small and recurved. The 3 succeeding segments successively 

 diminishing in width, and having the epimeral plates not much prominent 

 laterally. Last trunkal segment very small. Urosome not nearly attaining half 

 the length of the anterior division and much narrowed; genital segment com- 

 paratively large, occupying half the length of the urosome, and forming on 

 each side a broad lamellar expansion angular behind. Caudal rami very small, 

 quadrangular, with the apical setae rather slender and scarcely at all divergent, 



