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The frontal margin uninterrupted, with scarcely any hairs. The l)asal joint of the maxillipeds 

 moderately stout (fig. 1 d) , scai'cely longer than half the breadth of the head. The genital 

 area (fig. 1 e) not nearly twice as long as broad ; the whole area between the genital apertm-es 

 and the caudal stylets, a narrow part behind the latter, and an area outside the soft mem- 

 brane wIulIi borders the genital apertures, are covered with rather short hairs. The 

 remainder as in the preceding species. 



MALE. The well-developed specimen illustrated (fig. If and fig. Ig) is •17 mm. long 

 and -09 mm, broad, thus a little more than half the length of the largest female. The body 

 more clumsy than in the preceding species, not twice as long as broad. Frontal margin 

 and maxillipeds as in the female. Trunk-legs and caudal stylets shorter, not nearly half 

 as long as the breadth of the body, and with very few or no hairs. 



OVISACS. Rather large (fig. Ic), shortly ovate or sub-giobular. There may be 

 five to twelve, but generally we find six to ten comparatively extremely large eggs in each 

 ovisac, and as many as eight ovisacs have been found with one female. 



LARVA. In one ovisac were found larvse nearly on the point of swimming out; 

 one of these is figured (fig. Ih); its body is •15 mm. in length, and the cephalothorax is 

 very elongated. The olfactory seta of the antennulae reaches the posterior extremity of the 

 cephalothorax. Distance between the maxillae and the maxillipeds considerably shorter than the 

 basal joint of the latter. Second abdominal segment scarcely the length of the first. The 

 long setifi of the caudal stylets considerably shorter than in the preceding species, not half 

 the length of the cephalothorax and frequently much shorter. 



POST-LARVAL DEVELOPMENT. Unknown. 



HABITAT. In the branchial cavity of Iphinoe trispinosa (Goods.), at Messina. 

 In May and in the beginning of June 1893 I caught fifty-eight specimens in all ages of 

 this species in the harbour of Messina, in a depth of ten to twenty fathoms, and seven out of 

 these were infested with the parasite. It was only found in specimens which were either 

 much more than half-grown or full-grown, so that no parasite appeared on a single one of 

 the numerous specimens wliich were only half-grown or still younger. A female with the 

 marsupium containing Sphcpronella marginata (s. later on), had on its right hand side a 

 considerable swelling, in wliich were two adult females, tAvo males and six ovisacs. In a 

 female with less than half-developed marsupium, the left branchial cavity contained a male; 

 the right hand side of the carapace , especially its posterior part , bulged very much , and 

 under the hindmost part of it were found an adult female, in front of it a male and eight 

 ovisacs, the foremost of which was evidently newly laid, whereas another, which was lying 

 close up to the female, contained full-gro-mi young ones; tliis arrangement showed clearly 

 that the female had changed place. An adult male contained in its left branchial cavity 

 one half-grown female. Another adult male contained, also in its left hand side, one adult 

 female, one young female, one male and two ovisacs. The three remaining hosts, ^nz. a 

 male before its last moult and two not quite adult females, have not been dissected, but it 



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