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broad. The front has a curved list inside the anterior angle of each antennula (some trans- 
verse stripes shown in fig. 1f, I am unable to explain). Antennulze 3-jointed, olfactory seta 
comparatively short, not half the length of the cephalothorax. Antenne a little longer than 
the antennule, in all respects like those of Spher. 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. 1e) The maxillule consist of three moderately long naked branches, which 
spring from a low eminence. The joints of the maxillze 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 sets 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 setse about °/1 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 pupz (fig. 1g—1k) 
of somewhat different shape and considerable difference of size. With regard to these pupz 
I refer to p. 56—57 where a detailed account of them is given. 
HABITAT. The branchial cavity of Hippolyte Gaimardii 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 larve; 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- 
most 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 2/3 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 mn. 
in length, moreover, in the two foremost of the gills of the trunk-legs, occurred numerous 
pup and hinged larvz in all stages transitional to that of the pupa, altogether twenty-one 
pup and fourteen larvee; the hindmost gills also revealed some larve and pup, but each 
of them only a few, except the penultimate, which contained many at one end. The larve 
and pups 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. 
