208 



branchiata. In the female, moreover, the coxal plates are much more fully de- 

 veloped, forming together a broad continuous area flanking the sides of the meso- 

 some. Also the appendages of the metasome are rather different, the lamellae 

 of the pleopoda being much smaller and perfectly smooth, whereas the uropoda 

 are quite unusually elongated. 



Occurence. I have only seen 2 specimens of this form, the one ap- 



parently adult, or nearly so, the other evidently not yet fully grown, having the 

 incubatory plates in process of formation. Both these specimens are figured on 

 the accompanying plates, in order to show the differences. The young specimen 

 has the body less asymetrical, and of a rather regular oval form, and the coxal 

 plates are also more regular, forming on both sides of the mesosome a quite 

 continuous row ; but otherwise the 2 specimens agree exactly. They were both 

 found in the branchial cavity of Galathea dispersa, Sp. Bate. Messr. Giard and 

 Bonnier record likewise a species of Pleurocrypta from the same host, naming 

 it P. Hendersoni; but, as no description or figure has been given, it is impossible 

 to state, if these 2 forms are identical or not. That the statement alone of the 

 host is quite insufficient for identifying the parasite, is clearly proved by the 

 fact, that one and the same species of Crustacea not seldom is found to be in- 

 fested by several species of parasites, often belonging to very different genera 

 In the present case it may be mentioned, that a species of Pesudione, P. confusa 

 Norman, is recorded from the very same species of Galathea. 



3. Pleuroerypta microbranchiata, G. 0. Sars, n. sp. 



(PL LXXXVII, fig. 2). 



Specific Characters. Body of female broadly oval, rather asymetrical, 

 being twisted to the right or left hand, according to its place on the host. Ce- 

 phalon of moderate size, frontal edge slightly curved, lateral corners obtuse. 

 Segments of mesosome well defined, with the lateral parts slightly elevated ; coxal 

 plates less fully developed than in the 2 preceding species. Epimeral plates 

 of metasome discontiguous, lanceolate. Eyes distinct. Antennae, oral parts and 

 legs of the usual structure. Incubatory plates large, though somewhat apart in 

 the middle. Pleopoda comparatively small, with the lamellae perfectly smooth. 

 Uropoda of inconsiderable size, forming 2 small oblong lamellae. Male compara- 

 tively short and stout, depressed, oblong oval in form, with the greatest width 

 in de middle, metasome forming an undivided obtusely triangular piece. Colour 



