173 



broad. The front has a curved list inside the anterior angle of each antennula (some trans- 

 verse stripes shown in fig. If, I am unable to explain). Antennulae 3-jointed, olfactory seta 

 comparatively short, not half the length of the cephalothorax. Antennae a little longer than 

 the antenniilae, in all respects like those of Splicer, dispar, except that the broad basal part 

 sometimes seems clearly to consist of two joints (fig. 1 f), while sometimes only one joint is 

 discernible (fig. 1 e) The maxillulae consist of three moderately long naked branches, which 

 spring from a low eminence. The joints of the maxillae are smooth, the last one seems to 

 end in two extremely short points. Second joint of the maxillipeds a little shorter than the 

 third. The peduncle of the natatory legs fairly broad. First abdominal segment somewhat 

 longer and considerably broader than the second, and the setae of its posterior angles twice 

 the length of the following segments and the caudal stylets, exceptionally thick and hairy 

 on their distal half; third segment much smaller than the second; the caudal stylets pretty 

 well defined, and their setae about 3 A the length of the cephalothorax. 



POST-LARVAL DEVELOPMENT. On the gills of a Hippolyte appeared specimens 

 of all the transitional stages between larva and pupa, besides numerous pupae (fig. lg — Ik)' 

 of somewhat different shape and considerable difference of size. With regard to these pupae 

 I refer to p. 56 — 57 where a detailed account of them is given. 



HABITAT. The branchial cavity of Hippolyte Gaimarclii M.-Edw. from the Kara 

 Sea. In a female without eggs I discovered under a swelling of the carapace on the left 

 side: one female and twelve ovisacs, the contents of which presented the most different 

 degrees of development; in one ovisac, for instance, appeared full-grown larvae; the five 

 gills of the host, belonging to the trunk-legs, were all a little curled, the two foremost, 

 especially, were distinctly deteriorated. Beneath a large swelling of the carapace of another 

 female Hippolyte without eggs occurred one female and nine ovisacs, which, however, have 

 not been all taken out, nor the gills examined. In a third female without eggs one female 

 and six ovisacs appeared under a swelling on the right side of the carapace; the two fore- 

 must of the gills of the trunk -legs were atrophied, the three others were normal. A female 

 of the host with numerous eggs containing half-developed young ones, had on its right side 

 a swelling on the carapace about 2 k of the normal size, but parasites and ovisacs had dis- 

 appeared, and so had the two foremost of the gills of the trunk-legs; the three hindmost 

 were normal, without brood of parasites. There was no swelling on the left side of the 

 carapace, but far to the front appeared the small above-mentioned female which was 1/35 mm. 

 in length, moreover, in the two foremost of the gills of the trunk-legs, occurred numerous 

 pupae and hinged larvae in all stages transitional to that of the pupa, altogether twenty-one 

 pupae and fourteen larvae; the hindmost gills also revealed some larvae and pupae, but each 

 of them only a few, except the penultimate, which contained many at one end. The larvae 

 and pupae were attached to the surface of the foliaceous gill-fibres at their base ; sometimes, 

 though seldom, two were situated close to each other, sometimes they were found far in 

 between the origin of two gill-fibres. 



