196 



simple, conic; posterior antennae with the flagellum 4-articulate ; legs of uniform 

 structure; uropoda with the inner ramus shorter than the outer. Parasitic on 

 decapodous Crustacea. 



Remarks. This family comprises the more differentiated forms of Epica- 

 rida, in which the retrograde metamorphosis is less pronounced. Yet the adult 

 female in every case exhibits an appearance very different from that of the male 

 and the larvae, the body being more or less deformed and asymmetrical, though 

 its segmentation, as a rule, is distinct at least on the dorsal side, with the 3 

 chief divisions well defined. The greater number of forms are found as parasites 

 in the branchial cavity of higher Crustacea ; but there are a few forms which infest 

 the ventral or dorsal face of the metasome of their hosts, and which also in several 

 other respects differ considerably from the others, and might therefore perhaps more 

 properly be separated into a particular subfamily (the genera Athelges and 

 Phryxus). Rather a great number of genera have been established, especially 

 by M.M. Giard and Bonnier; but I believe that some of these genera are not 

 very well defined, so that a reduction may perhaps be found to be necessary. 

 In the following pages will be described 6 genera, at least 5 of which are 

 stated to belong to the fauna of Norway. 



Gen. 1. BOpyrUS, Latr., 1804. 



Generic Characters. Body of female broad, flattened, rather asymmetrical, 

 with the segments of mesosome firmly connected. Cephalon deeply immerged 

 within the 1 st segment of mesosome, frontal edge broad, lamellar. Lateral parts 

 of mesosome slightly elevated, subcontiguous, coxal plates inconspicuous. Meta- 

 some narrowed, with the segments confluent in the middle of the dorsal face, 

 epimeral plates distinct, subcontiguous, last segment resembling them. An- 

 terior antennre distinctly 3-articulate, posterior ones apparently consisting of 

 only 2 articulations. Terminal joint of maxillipeds well defined, broadly oval or 

 cordiform. 1st pair of incubatory lamella rather large, divergent, distal segment 

 terminating in a narrow linguiform lobe; the 4 succeeding pairs widely apart, 

 leaving a -broad open space in the middle, the marsupial pouch being here closed 

 by the carapace of the host. Legs very small, concealed within the lateral edges 

 of the mesosome. Pleopoda simple, lamellar. Uropoda wanting. Male with the 

 segments of metasome imperfectly defined. Parasitic in the branchial cavity of 

 prawns. 



