587 



Gren. 4. IschyrOCerUS, Kroyer, 1838. 

 Syn. : Podocerus, auctorum (part). 



Body more or less slender, with the coxal plates of moderate size; 

 4th pair the largest and scarcely emarginated posteriorly; 5th pair with tl it- 

 anterior lobe deeper than the posterior. Cephalon with the frontal part 

 somewhat produced and attenuated, lateral lobes small, snbangnlar, postanten- 

 nal corners rather deep, and defined in front by a distinct emargination 

 encircling the large basal joint of the inferior antennae. Eyes distinct or 

 obsolete. Antennae rather strongly bnilt, and densely setiferons posteriorly, 

 with elongated peduncles and comparatively short flagella; the inferior ones 

 being, as a rule, the longer, and subpediform, the superior ones provided with 

 a very small accessory appendage. Mandibular palp very large, with the 

 terminal joint lamellarly expanded and densely setiferons. Oral parts other- 

 wise normal. Grnathopoda in female comparatively feeble, the posterior ones 

 being but little stronger than the anterior, propodos in both pairs obpyriform, 

 with the palm imperfectly denned. Posterior gnathopoda in male much larger 

 than in female and sometimes peculiarly modified, but never exhibiting any 

 approach to a cheliform character. The 3 posterior pairs of pereiopoda much 

 larger than the 2 anterior ones, and, as a rule, strongly reflexed, basal joint 

 laminar. Branchial lamellae comparatively small; incubatory lamellae large 

 and broad. Last pair of uropoda projecting beyond the others, basal part 

 rather large and compressed, rami short and more or less hook-shaped, the 

 inner one generally with a number of small recurved hooks near the tip. Telson 

 small, triangularly pointed at the tip. 



Remarks. This genus was established by Kroyer in the year 18;>s, 

 to include a northern species, I. anguipes. By most subsequent authors it has 

 been combined with the genus Podocerus of Leach, to which it indeed bears 

 a very close relationship. It differs, however, materially in the structure of 

 the posterior gnathopoda, which in the female are far less strong than in that 

 genus, and in the male never exhibit any approach to the peculiar cheliform 

 character, distinguishing the genus Podocerus. Several species of the present 

 genus have been recorded, especially from the northern Oceans. To the 

 fauna of Norway belong 4 species, to be described below, one of which is 

 now for the first time established. 



