CRUSTACEA MALAC08TRACA. III. 



2ooi'W., 167 fath.; by the Ilnd Amdrnp Exp. in Forsblad Fjord, Lat. 72*17' N., 9040 fath. At East 

 Iceland it has been taken by Mag. R. Honing in Faskruds Fjord, 50 20 fath., and by the "Thor" in 

 Rode Fjord, 70 fath. Finally the "Thor" captured a male south-west of the Fscroes in Lat 61*15' N n 

 Ung. 9 35' W, 463-55 fa^i. 



Distribution. Sara recorded it as occurring "along the whole Fintnark coast" and "south- 

 wards to the Lofoten Islands"; furthermore from a station near Jan Mayen, 70 fath., temp. -4- 0-6, and 

 from a station between Finmark and Beeren Kiland, 191 fath., temp. 3-5. Ohlin mentioned it from 

 two places at Spitsbergen, in depths from about 35 to 60 fath.; the "Dijmphna" captured it in the 

 Kara Sea, 49 to 64 fath. (H. J. Hansen). 



The localities enumerated show that G. rlongata has a wide distribution and lives in depths 

 from a couple of fathoms down to about 500 fath., most frequently in temperatures alx>vc zero, but 

 also in temperatures down to at least -f- 0-6. 



159, Gnathia robusta G. O. Sars. 

 (PL XVI, figs.6a-6b). 



1879. Ancrus robustus G. O. Sars, Arch. Math, og Naturv. Vol. IV, p. 432. 

 ! 1885. G. O. Sars, North-All. Exp., Crust I, p. 94; PL 8, figs. 2527. 



The authorities of the University Museum in Christiania kindly lent me Sars' material, and an 

 examination of the 8 males rendered some results. The males vary considerably in size, the largest 

 being 6-6 mm. and the smallest only 4-3 mm. long, the mandibles not included. Somewhat less than 

 the proximal half of the upper side of the mandibles is raised as a kind of longitudinal keel always 

 annul with four to six triangular teeth (fig. 6 a), a feature overlooked by Sars. The front margin of 

 the head has at the middle a somewhat small or minute, more or less low, rounded or acute median 

 projection. The eyes are somewhat small. Head and thorax proportionately broad as figured by 

 Sars, but the degree of scabrousness originating from small teeth and sharp granules varies considerably, 

 as in some smaller specimens the two posterior segments are nearly smooth, and the convex sides of 

 the head, which in the largest specimens have numerous conspicuous acute teeth, have only a few teeth 

 or are nearly smooth in some other specimens. The thoracic segments have very few and short setae 

 on the sides. The abdominal segments either naked or with very few and short lateral seta:; the 

 major distal part of last segment is a narrow triangle as figured by Sars. 



The four males from the Danish expeditions agree as to size, structure, variation, etc. completely 

 with those mentioned. The median part of the front margin of the head is always distinctly produced 

 as a triangle, which is conspicuously broader than long and in one specimen very short and rounded, 

 while in another specimen this produced lamellar part has the margin somewhat irregular and the end 

 itself feebly emarginate. 



The female, which has not been described by Sars, is extremely thick, considerably thicker 

 than in G. rlongata Kr. or G. abyssorum G. O. Sars; it differs from both in having the anterior pot 

 of the head (fig. 6b) less produced, with the emargination considerably broader than in thaw females. 

 It differs from (',. rlongata and agrees with G. abyssonim in having nearly no setse on the front port 



. potato. III. f. *9 



