iKt >rui \ MALAC08TRACA III IO - 



umisctts. The ab<K>men is generally broader in the male than in the female, and in some species it 

 shows further sexual differences. The female operculum seems to be rather uniformly shaped; the 

 median lamella in the male operculum shows specific differences, but they are sometime?, difficult to 

 investigate without dissection. 



The single character between fifsmosotna and FMgfrJa is drawn from the number of rami in 

 tlu- uropods. But this character cannot be of generic value, as, for instance, A. armahiih G. O. Sars, 

 which has no exopod on the uropods, is in the structure of the legs, etc, very closely allied to // 

 grrJat coarctatvm G. O. Sars or D. (Eug<rda> polihtm n. sp., which both have biramous uropod*; 

 /' ,irmatum is in reality more closely allied to these two species than to such forms with single-branched 

 uropods as D. lintarr G. O. Sars or A. insignf n. sp. Therefore the genus Kttgrrda must be suppressed 

 as not only valueless but misleading. 



From the North Atlantic with ramifications like Skager Rak, Kattegat, and the Mediterranean, 

 9 species were known, described by Sars, Meinert, Bonnier, and Stephensen. Of these only 3 are repre- 

 sented in the material from the "Ingolf area, but I here establish 8 new species. Thus no less than 

 1 7 species are known from the North Atlantic, including the cold area. I have, however, mutilated 

 specimens of still 5, or more, new species, but, as the specimens have lost the main part of the two 

 anterior pairs of legs, I do not think it advisable to describe them. 



These seventeen species may be divided into two sections, and determined by the aid of the 

 following keys. The species not found in the "Ingolf area are put in brackets and without number. 

 Sect I. First pair of legs with fifth and sixth joints slender; fifth joint has the lower margin either 



glabrous or with some few hairs or stiff setae. 



Sect II. First pair of legs with fifth and sixth joints much thickened; especially fifth joint is very 

 thick, with a very long and strong spine on the lower distal angle and in several species, besides, 

 with a single spine or a few strong spines along the lower margin. 



Section I. 



A. Uropods biramous. Fifth joint of first pair of legs with the lower margin either naked or bearing 

 a couple of hairs. (First thoracic segment only about half, or less than half, as long as the second (. 



a. Fifth and sixth joints of first pair of legs extremely thin and elongate; fifth joint many times 

 longer than thick (D. tmuimanum G. O. S.) 



b. Fifth and sixth joints of first pair of legs slender; fifth joint at most nearly five times as 

 long as deep. 



a. Epimera of second thoracic segment triangular, with the anterior half acute or obtuse. Fifth 

 joint of second pair of legs distinctly more than twice as long as deep, with 911, rarely 

 7 or 8, spines and setse along the lower margin I. D. glebuffi Mein. 



ft. Epimera of second thoracic segment with the anterior half rounded in front Fifth joint of 

 second pair of legs scarcely twice as long as deep, with 7 extremely strong, thick spines 

 along the lower margin . 2. D. latifies n. sp. 



B. Uropods without exopod. Fifth joint of first pair of legs with some setc on the lower margin, the 



most distal seta at least half as long as sixth joint 



4' 



