KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 22. N:0 7. 205 



Stebbing, does not point out this peculiarity in his description, but in the drawitig it is 

 distinctly expressed. If I had not had myself access to specimens strictly agreeing with 

 the features shown in his drawing I should have hesitated to use the non-coalescence of 

 the first peraeonal segment as a specific characteristic, and I should have placed H. dys- 

 schistus in the neighbourhood of H.thoracica which has the first five personal segments 

 coalesced. But as in my specimens the suture between the first and the following seg- 

 ments is to be plainly seen running all the way from the right epimeral to the left, I have 

 adopted this characteristic as most easily distinguishing H. dysschistus from its con- 

 geners. Stebbing's figures being very good I give here only two drawings from a young 

 male specimen, together with some supplementary characteristics as in the case of the 

 preceding species. 



T h e m a 1 e. 



The body is thick and stout, comparatively broader than in any of the preceding 

 species, except Hyperia medusarum. The head and peraeon together are shorter than the 

 pleon and urus together. The surface of the body is hard and shining. 



The head is longer than in the female, almost half as long as the coalesced portion 

 of the perseon. 



The perwon. The first segment is longer than the sixth, and fully as long as the 

 seventh. 



The epimerals are as long as the under margins of the corresponding segments, and 

 almost as deep as long. 



The first pair of perwopoda (PI. XI, fig. 1). The femur is as long as the three 

 following joints and half the fourth. The carpus is dilated and produced; the front 

 margin of the carpal process is scarcely a third part as long as the hind margin of the 

 metacarpus. The metacarpus is elongate-ovate, and much longer than the stem of the carpus; 

 the front margin carries a single bristle a little below the middle; the hind margin is 

 finely serrated, with simple teeth. The dactylus is half as long as the metacarpus, being 

 finely serrated on the hind margin. 



The second pair (PI. XI, fig. 2) are somewhat longer than the first pair, and reach 

 a little below the middle of the carpus of the third pair. The femur is somewhat shorter 

 than the four following joints together. The front margin of the carpal process is fully 

 half as long as the hind margin of the metacarpus. The metacarpus is a little longer 

 than the stem of the carpus; the front margin carries a single bristle; the hind margin 

 is serrated as in the first pair. 



The third and fourth pairs. The femur is fully as long as the three following 

 joints. The tibia is longer than the genu, and a little dilated, with a bristle at the lower 

 hind corner; the hind margin is smooth. The carpus is as broad as the tibia and only 

 a little longer; the hind margin is finely serrated, and has a single bristle at the lower 

 corner. The metacarpus is about as long as the two preceding joints together, and only 

 a little shorter than the femur; the hind margin is serrated, without bristles. The dactylus 

 is about half as long as the metacarpus. 



