Ifi3 



curved list in advance of the base of the antennula; from the margin, in front of this list, 

 runs a transverse series of shorter processes; finality, fiom the part before the rostrum, 

 extending outward and forward up to the anterior margin, we see an area covered with 

 some rows of similar processes placed close together. The olfactory seta of the antennulae 

 extends at least far back on the second abdominal segment. The antennae ditfer widely from 

 those of the four preceding species; they are short, 2-jointed, the first joint is moderately 

 long and rather tliick, the second joint is only half its length and ends in two setae, one 

 of which is short, the second a little longer than the first joint. The innermost and foremost 

 branch of the maxillulae, Avhich e. g. in S. dispar is situated far in tront of the three other 

 branches, in S. marginata is placed further backward, so as to be nearly at the same height 

 as the two branches closest to it, besides being reduced to a short process; the outermost 

 branch here is shorter than the two intermediate ones, and seems, moreover, to be naked. 

 First joint of the maxillae as in the four preceding species, second joint without tenninal 

 setae, the tliird one (fig. 6h) serrated, having some very fine acute processes at its inner 

 margin. Second joint of the maxillipeds short, third joint exceptionally long, several times 

 the length of the second. Abdomen comparatively somewhat smaller than in the nearest 

 preceding species, but the mutual dimensions between the segments are the same; the long 

 setae of the first segment extend pi-etty considerably beyond the end of the caudal stylets, 

 and the terminal setae of these stylets are more than half the length of the body. 



POST-LARVAL DEVELOPMENT. Unknown. 



HABITAT. The marsupium of Ix)hino'e frispinosa (Goods.) from Messina. In a 

 specimen which had Homoeoscelis mediferranea (s. p. 97) in its branchial cavity occurred: 

 one female, one male and four ovisacs containing larv*. Tliis was the only specimen 

 infested with this parasite in the material mentioned more specially above on p. 97. 



REMARKS. The most noteworthy featiu'e in this interesting species is no doubt 

 that its maxillae as well as its maxillipeds difler so much in the two sexes, and at the 

 same time, in both sexes, especially in the female, deviate widely fi-om these appendages 

 in all other hitherto known species, not only of this genus, but of the whole family. 



a. Parasites on Isopoda. 



In thi'ee species of Isopoda, all belonging to the group Asellota, I have discovered 

 three species of the genus SpheproncUa. The females of two of the species show great 

 similarity to the normal species of the genus wliich live on Amphipoda, but the thiid species 

 deviates very considerably fi-om these parasites. The only charactei's connnon to the females 

 of all three species are: antennae seem to he wanting; the mouth is large with a broad or 

 very broad mouth-border, the hairs of which are remarkably thick; the maxillula:' are well 

 developed, with long principal branches and at least very distinct additional branch; the 



21* 



