179 
For my whole abundant material of this and of the following genus I am indebted 
to Professor G. O. Sars. It consisted partly of infested Mysida 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 Myside of Norway, but I have felt bound to follow Steb- 
bing in adopting the older names of two of the species. — Besides, in his »Report on the 
Challenger Schizopoda« G. O. Sars himself mentions having observed in the genus Erythrops 
»a peculiar Lernzid, apparently the Spheronella leuckartii of Salensky«, otherwise he does 
not give any more details about his finds. 
Conspectus of the Species. 
1. The Females. 
Antennz almost rudimentary, 1-jointed. Head naked... .. . 1. M. commune Nn. sp. 
Antenne larger, 2-joited. <A lateral longitudinal belt on the head and a conside- 
rable area behind the maxillipeds covered with hairs.......... 2. M. abyssorum 0. 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... .. 7. 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 
AVL AC CMO SUM ease ees euncter sac TNs Jep'e rats, sbi sel gfescictea,.2) '» Giroyar ems 2. M. abyssorum. 
|. Mysidion commune n. sp. 
(PI. XI, fig. 3a—3i; pl. XII, fig. 1a—14d). 
FEMALE. In fig. 3a 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 
23mm. broad. The female represented in fig. 3b is more normal, large, and had probably 
not finished laying eggs; it is 114mm. in length and ‘94mm. in breadth, shortly ovate, and 
23* 
