161 



minent character of the present genus is the very peculiar structure of the man- 

 dibular palp, to which also Boeck has called attention. Moreover the feeble 

 development of the posterior maxillipeds, and the peculiar shape of the last pair 

 of legs, are characteristic features of this genus. Finally the rostrum is quite 

 immobile, and in form also differs from that in the 2 preceding genera. We 

 know at present of 8 species belonging to this genus. 7 of which occur off the 

 Norwegian coast, and will be described below. 



119. Stenhelia gibba, Boeck. 



(PI. CXIX & CXX, fig. 1). 



Stenhelia gibba, Boeck, Oversigt over de ved Norges Kyster iagttagne Copepoder. Chr. Vid. Selsk. 



Forhandlinger f. 1864, p. 271. 



Syn: Delavalia mimica, Scott. 

 Beatricella mimica, Scott. 



Specific Characters. Female. Body rather robust, pyriform, with the ce- 

 phalic segment very large and tumid, being gibbously vaulted above. Rostrum 

 triangular, about as long as it is broad at the base, tip obtusely blunted and 

 defined on each side by a distinct ledge carrying a small hair. Urosome much 

 shorter than the anterior division, and rapidly tapered distally, genital segment 

 scarcely constricted in the middle, though much broader in front than behind. 

 Caudal rami scarcely divergent, being about twice as long as they are broad, and 

 transversely truncated at the tip, apical setse rather slender. Anterior antennae 

 much shorter than the cephalic segment, and somewhat curved, 1st joint much the 

 largest, being about as long as the 2 succeeding joints combined, terminal part 

 somewhat exceeding half the length of the proximal part. Posterior antennae with 

 the outer ramus about the length of the last joint of the inner, and carrying 6 

 setse, 3 apical and 3 lateral, middle joint short, the other 2 of about equal size. 

 Posterior maxillipeds small, with the hand somewhat lamellar, dactylus short but 

 distinctly biarticulate. 1st pair of legs with the outer ramus shorter than the 

 1st joint of the inner, middle joint without any seta inside, last joint somewhat 

 smaller and obliquely truncated at the end, carrying 3 slender spines and a still 

 more slender seta inside them; inner ramus distinctly triarticulate and sub-pre- 

 hensile, 1st joint very large, being about 3 times as long as the other 2 combined, 

 the latter subequal in size and bent at an angle to the 1st, last joint armed on 

 the tip with a slender claw-like spine, an elongated seta, and a small hair-like 

 bristle. Inner ramus of the 2 succeeding pairs about the length of the outer, 

 that of 4th pair much shorter, not extending beyond the 2nd joint of the outer. 



24 Crustacea. 



