590 



angular. Eyes small, rounded, with dark brown pigment. Antennae some- 

 what variable in length, now comparatively short and stout, now rather 

 slender and elongated; flagellum of the superior ones composed of 5—6 

 articulations, accessory appendage somewhat shorter than the 1st articulation 

 of the flagellum. Inferior antennae in male, as usual, much more strongly 

 built than in female. Gnathopoda in female nearly as in the preceding species, 

 though having the palm of the propodos more clearly defined. Posterior gnatho- 

 poda in male very much elongated, ischial joint expanded above to a rounded 

 compressed lobe, meral joint obtuse in front, propodos very large, and, as 

 in the preceding species, comparatively narrow in proportion to its length, 

 being, however, not at all curved, but quite straight, with the lower edge 

 even slightly convex in the middle, and forming anteriorly a very conspicuous, 

 almost clavate prominence issuing at a right angle to the propodos ; dactylus 

 very strong and curved, impinging, when closed, with the tip aboTit in the 

 middle of the lower margin, its inner edge being at the same time in close 

 contact with the above-named clavate prominence. The 2 anterior pairs of 

 pereiopoda about as in I. anguipcf, the 3 posterior pairs, on the other hand, 

 comparatively stouter, with the basal joint broader, and having the hind edge 

 slightly crenulated. Last pair of uropoda with the inner ramus shorter than 

 the outer, but much broader in its proximal part, and having 3 recurved 

 denticles on the upper edge near the tip. Telson with only a single pair of 

 dorsal spines. Colour somewhat variable, now yellowish green with numerous 

 dark specks, now whitish with brownish red transverse bands. Length of 

 adult female scarcely exceeding 4 mm, of male but little larger. 



Remarks. — There . cannot, I think, be any doubt, that the above 

 described form is that recorded by Prof. Lilljeborg as Ischyrocerus mimdus, 

 and that the Podocerus isopus of Walker is the same species. It is very 

 nearly related to /. nmiuipex. and has probably by most other authors been 

 confounded with this species. On a closer examination, it is, however, found to 

 differ not only in its very inferior size, but also in the somewhat more strongly 

 built posterior pereiojDoda, the shape and armature of the last pair of uropoda 

 and of the telson, and especially in the rather diiferent structure of the 

 posterior gnathopoda in the male. 



Ocnirrence. — The species occurs very abundantly along the whole 

 south and west coast of Norway in comparatively shallow water among algae, 

 and is not infrequently met with in rock-pools left by the tide. 



Distribution. — Bohuslan (Lilljeborg), British Isles (Walker). 



