123 



OVISACS. They are of middle size; those hitherto found are somewhat irregular 

 from pressure, obloug (fig. 2a), the longest - 69 mm. long. The eggs large, not numerous. 



LARVA and POST-LARVAL DEVELOPMENT. Unknown. 



HABITAT. The marsupium of Astyra abyssi Boeck from Einmarken (Norway). 

 In one specimen were found: the female mentioned, with the two ovisacs glued together and 

 adhering to its foremost part, and a third one glued to its ventral surface, besides two males, 

 one of which was fastened by the frontal thread shown in the drawing. In another specimen 

 were found only four ovisacs, and these were discovered in examining some specimens of 

 the above-mentioned Amphipod kindly offered to our Museum by Prof. G-. 0. Sars, upon which 

 on my applying to him, he lent me his whole material for investigation, and I discovered 

 the specimen which supplied me with both sexes of the parasite. 



REMARKS. The description of the female is, unfortunately, very defective on 

 account of the loss of the head. The male is exceedingly characteristic owing to the 

 unique development of the terminal setae of its trunk-legs and caudal stylets. 



13. Sphaeronella Argissae n. sp. 



(PL IV, fig.3a-3n). 



EEMALE. The only adult specimen (fig. 3 a) was somewhat shrunk and rendered 

 crooked by pressure ; its length was -85 mm.; a small, recently hatched specimen represented 

 in fig. 3 c (enlarged on the same scale as fig. 3 a) and strongly magnified in fig. 3 d, is crooked 

 and empty; its length is 15mm.. The head is small and well defined. The frontal margin 

 is naked. The antennulae have moderately long terminal setae. The antennae are 3-jointed, 

 their terminal seta quite as long as the last joint. The mouth-border of medium breadth. 

 The maxillulae with additional branch. The maxillae smooth. The maxillipeds slender, 

 their basal joint naked, the following three joints distinctly separated, the terminal joint 

 pointed. The sub-median skeleton has narrow longitudinal lists inside the maxillae and no real 

 transverse list at the median line behind the base of the maxillipeds; it is naked all over. 

 The lateral margin of the head provided with rather short and fine hairs. The trunk quite 

 naked; the trunk-legs well developed in the young ones, and probably also present in the 

 adults. The genital area (fig. 3f) broader than the head (fig. 3a), somewhat broader than 

 long; the solid chitine forms a semi-circle which opens towards the front; it is very broad 

 posteriorly and decreases gradually in breadth; its two extremities form irregular lobes 

 with inward curving points; the posterior margin is semicircular. The genital apertures 

 oblique, the distance between them of medium length (in fig. 3f they are wide open and 

 a spermatophore is attached to the entrance of one of the receptacula seminis). The caudal 

 stylets are small but well developed and situated close together on the firm chitine imme- 

 diately behind the genital apertures. The whole genital area is naked (the young one 

 represented in fig. 3d has no genital area yet). 



l«* 



