330 CRUSTACEA MALACOSTRACA. III. 



long as broad and comparatively small; the angles at the insertion of the antennulae protrude as small 

 processes, and the sides behind these angles are very convex, even subangular at the middle. Some 

 fine granules are observed ou the sides of the head and on a smaller sublateral part of the upper 

 surface; this surface is deeply excavated in the middle of nearly its anterior half; the head is much 

 produced between the mandibles, and the front margin, which is somewhat damaged, seems to have 

 been rather short and considerably emarginate. Eyes wanting. - The mandibles in the main as in 

 G. albescens, without teeth on the proximal half of the upper margin, and the protuberance at the end 

 of this half low and feebly developed. Antennulae and antennae rather short; the flagella 5-jointed. - 

 Maxillipeds as in G. albescens; the shield-shaped first pair of legs as in G. elongata. 



Penultimate leg-bearing thoracic segment undivided in the middle, laterally considerably widened, 

 only a little shorter than the sum of the two preceding segments. The surface and sides of the thoracic 

 segments are smooth, and even the sublateral areas on the penultimate segment are badly defined. - 

 Thoracic legs (fig. 10 b) a little thicker than in G. albescens; fifth joint unarmed or with a single 

 tubercle or, in a couple of legs, with two protuberances on the lower margin; the articulated spines 

 are somewhat long and slender and few in number, while the legs have a good number of long setae, 

 many of them plumose. 



The abdomen decreases conspicuously in breadth backwards; the five anterior segments with- 

 out protruding lateral angles. Pleopods without setae. Last segment (fig. 10 c) nearly more than half 

 as long again as broad, with the major distal part moderately narrowed and the end acute; it over- 

 reaches somewhat the uropods, which have the rami subequal in breadth. 



Length 4-1 mm. - - The specimen has the head white, while the remainder of the body is dark 

 olive-greenish, and dark reddish contents of the large central part of the thorax are very visible through 

 the integument. 



Remarks. G. bicolor is easily separated from the above-described blind G. albescens by a 

 number of features, especially by the shape of the head, the last abdominal segment, and the colour. 



Occurrence. Taken by the "Ingolf" in the warm area. 



South of Iceland: Stat. 40: LaL 62oo' N., Long. 2i^6' W., 845 fath., temp. 3-3; i spec. (c?). 



164. Gnathia stygia G. O. Sars. 



1877. Anccus stygius G. O. Sars, Archiv. for Math, og Naturv. Vol. II, p. 348. 

 ! 1885. G. O. Sars, North-Atl. Exp., Crust. I. p. 85; PI. 8, figs. 122. 



1901. Gnathia stygia A. Ohlin, Bih. K. Sv. Vet Akad. Handl. Vol. 26, Afd. IV, No. 12, p. 22, fig. 3. 

 1901. Caccognathia stygia Dollfus, Bull. Soc. Zool. France, 1901, p. 244. 

 Sarsi Dollfus, ibid. p. 244, fig. 3. 



Dollfus established C. Sarsi on a single male taken together with four males of C. stygia, but 

 the characters pointed out by him are of no value; all are due to individual variation. Among his 

 characters the best seems to be that in C. Sarsi the last abdominal segment terminates "en pointe 

 aigue" and its sides are "nettement dentes", but the males from the "Ingolf show considerable indivi- 

 dual variation in the shape and armature of this segment, as in one specimen it has the rounded end 



