179 



For my whole abundant material of this and of the following genus I am indebted 

 to Professor (x. 0. Sars. It consisted partly of infested Mysidse with indication of their 

 localities, partly of similar animals without such indication, further, of parasites taken out 

 of their hosts, the latter not being mentioned; these last animals have scarcely been used 

 at all. I have determined the hosts in accordance with the above-mentioned naturalist's well- 

 known excellent work about the Mysidse of Norway, but I have felt bound to follow Steb- 

 bing in adopting the older names of two of the species. — Besides, in his »Eeport on the 

 Challenger Schizopoda« G. 0. Sars himself mentions having observed in the genus Erythrops 

 »a peculiar Lernseid, apparently the Sphwronella leuclcartii of SalensJey«, otherwise he does 

 not give any more details about bis finds. 



Conspectus of the Species. 



1. The Females. 



Antennae almost rudimentary, 1-jointed. Head naked 1. M. commune n. sp. 



Antennae larger, 2-jointed. A lateral longitudinal belt on the head and a conside- 

 rable area behind the maxillipeds covered with hairs 2. M. dbyssorum n. sp. 



2. The Males. 



The head tapering considerably towards the front, provided with a narrow frontal 

 border. The basal joint of the maxillipeds has on its outer side a shorter process in the 

 centre and a long one at its distal end. The trunk is covered with innumerable minute 

 transverse eminences, from each of which project several short hairs 1. M. commune 



The head anteriorly broad, almost truncate, with a moderately broad frontal border. 

 The basal joint of the maxillipeds has on its outer side only a single tolerably large process 

 placed at its distal end. The trunk is without transverse eminences, the hairs normal, of 

 average length 2. M. dbyssorum. 



I. Mysidion commune n. sp. 



(PI. XI, fig. 3a— 3i; pi. XII, fig. la— Id). 



FEMALE. In fig. 3 a are represented the essential contents of a marsupium, con- 

 sisting of a shrivelled female and seventeen ovisacs ; the whole bulk was 2'9 mm. long and 

 2-3 mm. broad. The female represented in fig. 3b is more normal, large, and had probably 

 not finished laying eggs; it is 1-14 mm. in length and -94mm. in breadth, shortly ovate, and 



23* 



