241 



whitish, banded with irregular, reddish-orange patches, more largely developed 

 on the ;-5rd and 4th segment of mesosome and corresponding coxal plates; 

 ova in the mai'snpial poucli dark bluish. Length of adult female scarcely 

 exceeding 3 mm, 



Bt'innrJiS. — This form, described as eaidy as 1807 by Colonel 

 Montagu as Cancer gammarus monoculoidcs, is a very distinct and easily 

 recognizable species, differing, as it does, in several points very markedly, 

 not only from the type species, iS*. marina, but also from the other species 

 belonging to this genus. Even in the structure of the oral parts some 

 well-marked differences are to be found, and perhaps, therefore, this form 

 should more properly be separated as the type of a distinct genus. 



Occurrenre. — In habits, it is a true littoral form, ocurring, as a 

 rule, only close to the shores among algse. Still more frequently, it is 

 found at low water mark in shallow pools left by the tide, especially in 

 such, whose bottom is overgrown with algae and Hydroida. I have met 

 with it in seA^eral places, both off the soiith and west coast of Norway, and 

 northwards to Bejan, at the entrance of the Trondhjemsfjord. 



Dishibufion. — British Isles (Montagu, Sp. Bate), Kattegat (Meinert), 

 coast of France (Chevreux). 



5. Stenothoe brevicornis, G. 0. Sars. 



ij^l. 82, fig. -2) 

 Stenothoe brevicornis, G. O. Sars, Oversigt af Norges Crustaceer I, p. 89, PI. 4, fig. 1. 



Body comparatively robust, and but little compressed, though some- 

 what less compact than in S. monoctdoides. Cephalon rather small, and 

 scarcely produced in front, lateral corners but little produced, and obtusely 

 angular at the tip. Coxal plates of moderate size, 2nd pair scarcely 

 expanded distally, and rounded at the end; 3rd pair considerably larger, 

 and distinctly expanded in their outer part; 4th pair about as large as the 

 2 preceding pairs combined, and obtusely angulated posteriorly, distal edge 

 obliquely curved. Last pair of epimeral plates of metasome but little 

 produced, and nearly rectangular. Eyes of moderate size, rounded, with 

 well-developed visual elements and dark red pigment. Antennse comparatively 

 short; the superior ones scarcely exceeding Vs of the total length, 1st joint 

 of the peduncle about the length of the cephalon, 2nd joint somewhat 

 shorter, 3rd very small, flagellnm scarcely longer than the peduncle, rather 

 slender, and composed of about 12 articulations. Inferior antennae, about 

 the length of the superior, the 2 outer joints of the peduncle equal-sized, 



