225 



contained in the marsupial cavities is rather considerable in fully grown females, 

 though not nearly so immense as in the Bopyridse. They show with great di- 

 stinctness through the thin body-walls bounding these cavities. 



Distribution. Greenland (Kr0yer), Labrador (Packard), Sabine Island 

 (Buchholz), Spitsberg (Hoek), Jan Mayn (Norw. North Atl. Exped.), the Murman 

 coast (Stuxberg), the Kara Sea (Hansen). 



Gen. 2. NOtOphryXUS, G. 0. Sars, 1882. 



Generic Characters. Body of adult female ovate, more or less depressed, 

 and but slightly curved, with the cephalic part projecting in front, and the lateral 

 parts greatly swollen, though scarcely expanded anteriorly. Metasome forming 

 a semicircular, incurved plate, without any appendages. Marsupial rooms sub- 

 contiguous in the middle of the ventral faces. Antennse lamellar, imperfectly 

 articulated. Oral area rather small, contracted behind. Tips of mandibles pro- 

 jecting from the oral cone in the shape of 2 narrow plates armed with recurved 

 teeth. Maxillipeds folded hackwards over the very large and broad sternal plate. 

 Only a single pair of incubatory plates present, issuing from the base of the anterior 

 pair of legs, and divided into 3 diverging lappets. Legs small, of normal structure. 

 Adult male resembling that of Dajus. Larvae in the 1st stage distinguished by the 

 large size and peculiar structure of the uropoda. Parasitic on Mysidse and 

 Euphausiidse, being, as a rule, attached to the dorsal face of their hosts. 



Remarks. Though in the general appearance of both sexes this genus 

 is rather like the genus Dajus, it is found, on a closer examination, to differ in 

 several respects very pronouncedly. Thus, the antenna, at least in the type 

 species, exhibit a rather anomalous appearance, forming broad, inarticulate 

 plates, which together constitute a broad lamella bounding the oral area in 

 front. Moreover, the maxillipeds, instead of being turned anteriorly, are folded 

 hackwards over the large sternal plate, looking at first sight merely like a pair of 

 incubatory plates. Of the latter there is only a single pair present, issuing from 

 the base of the 1st pair of legs, and exhibiting a very irregular form. Finally, 

 there is no trace of any appendages on the metasome. Four different species 

 have been recorded by the present author as belonging to this genus ; but, as 

 remarked by MM. Giard and Bonnier, it is very probable that some of these 



29. Crustacea. 



