CRUSTACEA M.M.ACOSTRACA. HI. a| . 



skin excepting at the mouth, where the skin and the inner body are united ; that the content* are thu 

 removed from the skin is certainly due to the influence of the alcohol. The contents show no differ- 

 entiation, as ova are not developed. The reduced mouth (fig. a b) could not be really investigated, as 

 the single specimen ought not to be sacrificed. -- As to external features, nothing more than is stated 

 in the generic diagnosis could be made out 

 Length 3-8 mm. 



Male. Slightly more than three times as long as broad (fig. ac). Head with the anterior 

 margin broadly and evenly rounded. Eyes wanting. Antennuhc rattier large (fig. 3 d); first joint 

 (fig. ae) with the anterior margin moderately short; the outer margin very long, concave to near 

 tin- convex, short posterior part; posterior margin sinuate; the posterior part of the inner margin is 

 serrate, with two large, oblong, blunt teeth, and at each side of these a smaller, acute, triangular tooth. 

 Second joint proportionately large, with the anterior margin long and terminating in an acute tooth; 

 the terminal part of the joint divided by linear incisions from the outer margin into four lobes, and 

 two triangular protuberances are seen on the lower surface, not far from the margin. A bundle of very 

 long sensory- seta.- has, seen from below, its proximal part overlapped by the lobes mentioned, as the 

 part of the third joint bearing these hairs is completely covered, while the two rami belonging to 

 third joint are well developed. - The antennae reach about to the middle of fifth thoracic segment. 



Thoracic segments with the anterior pairs of epimera scarcely serrate, the posterior pairs dist- 

 inctly serrate on their hind margin. - - First (fig. a f) and second pairs of legs with the hand thick 

 and somewhat short, yet more than half as long again as deep. Fifth pair (fig. a g) rather slender; 

 the hand nearly four times as long as deep, deepest somewhat from the end, and there with a tiny 

 tooth on the lower margin, and near that tooth about three spines project on the posterior surface; 

 seventh joint scarcely marked off from the claw, and both combined a little more than half as long 

 as the hand. Sixth pair (figs, ah and a i) differ much from fifth or seventh pairs; the hand is about 

 five times as long as deep, broadest at the base, tapering to the rather narrow end, and with two 

 spines near the lower margin ; seventh joint, which is most peculiar, has been mentioned in the diagnosis 

 of the genus, and it may be added that it is somewhat more than one-third as long as the sixth joint, 

 and a distal area, marked off on the figure by a thin line, is quite thin and pellucid ; the slender claw 

 is about one-third as long as seventh joint Seventh pair (fig. a k) have the hand nearly more than 

 five times as long as deep, with two spines near the lower margin, but it is deepest at the middle 

 and distally slightly tapering; seventh joint with claw claw-shaped, about two-thirds as long as sixth 

 joint Pleopods normal (fig. al), with both rami well developed. Sixth abdominal segment without 

 teeth on the posterior margin; the uropods have both rami marked off by articulation. 



Length 1-6 mm. 



Occurrence. Found in the marsupium of AstaciUa g ranulata G. O. & and Plfurofirum kyslrix 

 G.O.S.; the hosts have been taken by the "IngolP. 



South-East of Iceland: Stat 4: Lat 64O7' N n Long. iiia' W., 237 fatlu, temp. 3-5; i specimen of 



AstaciUa granulata G. O. S. with a female and a male parasite in the 

 marsupium. 



