276 



hibits sexual characters quite analogous to those found in some species of that 

 genus, for instance L. Stromi and allied forms. 



Occurrence. I have only met with this form in a single locality, viz., in 

 a shallow bay near Christiania. It occurred here not infrequently close to the 

 shore, on a muddy bottom, males and females being present in about equal number 

 and often seen tied together in copulation. Th. Scott also records this form from 

 the Finmark coast. The movements of the animal consist chiefly in a slow creep- 

 ing through the loose mud in which it dwells, and with which the surface of the 

 body is often thickly covered. During these movements the very flexible body is 

 twisted in various ways, and both the antennae and the legs swing to and fro. 

 At times the animal is seen slowly climbing up the walls of the vessel in which 

 it is observed ; but I have never seen it make even the slightest attempt to swim, 

 and, indeed, the structure of the natatory legs, at any rate in the female, seei 

 to render the animal quite unfit for such a movement. 



Distribution. British Isles (Brady), Novaja Zemlja (Scott). 



182. Platychelipus laophontoides, G. 0. Sars, n. sp. 



(PL CXCII). 



Specific Characters. Female. Body somewhat less robust than in the pre- 

 ceding species, though otherwise of rather a similar appearance, tapering gradu- 

 ally behind. Cephalic segment exceeding in length the 3 succeeding ones combined, 

 rostral projection minutely bilobular at the tip. Urosome comparatively more 

 elongated, with the last segment fully as large as the preceding one. Caudal ranii 

 about twice as long as they are broad, and somewhat tapered distally; setae of 

 outer edge, like the dorsal one, issuing a little behind the middle, medial apical 

 seta somewhat exceeding half the length of the urosome, and not jointed at the 

 base. Anterior antennae comparatively more slender than in the type species, 

 with the setae of the anterior edge less strong, terminal joint considerably longer 

 than the 3rd. Posterior antennae with the outer ramus extremely small, and 

 having one of the setae much longer than the others. Mandibular palp compara- 

 tively smaller than in P. littoralis, though of a very similar structure. 1st pair 

 of legs likewise exhibiting the structure characteristic of the genus, outer ramus, 

 however, comparatively narrower than in the type species, with the last joint longer 

 than the 1st, and carrying 3 spines and 2 minutely ciliated setae; apical claw of inner 

 ramus very slender, and evenly curved at the tip. Natatory legs with the outer 

 ramus less strongly built than in P. littoralis, and provided inside with a few 



