CRfSTACBA MALACOSTRACA. III. 



hosts, others, viz. Cyfironucus and Ltriafsit, are firmly attached by having a part of their body deeply 

 imraerged within the body of their hosts. Unfortunately our knowledge of the females is still extremely 

 poor; of most of the species only a single specimen or very few specimens were found, with the result 

 that the descriptions of these difficult animals are imperfect; furthermore several species of lame in 

 the second stage or males were taken pelagically and have been described, but their females and con- 

 sequently their hosts are unknown. At the present state of our knowledge it seems to me impossible 

 to divide the Cryptouiscidae into subfamilies based on good characters in both sexes. 



The material from our area comprises five species belonging to five genera, and four among 

 these are new. And it may be seen that the extreme difference between the females of two geucra 

 found in the marsupium of the same species of Isopoda, while their males are closely allied, seems to 

 increase the difficulties as to a natural classification. Some larvae in the second stage or males taken 

 pelagically are omitted, as a representation would be of slight value. 



ClypeoniSCUS Giard & Bonnier. 

 Of the two species known only one has been found in our area. 



I 53- Clypeoniscus Meinerti Giard & Bonnier. 

 (PL XV, fig. 173; PL XVI, figs, i a-i c). 



1895. Clypeonisnu Meinerti Giard & Bonnier, BulL Sci. France et Belgique, Vol. XXV, p. 422428, 



p. 444; PL VII, figs. 20-21; PL VIII, figs. 24, 2627; PL X. 



The French Zoologists established contemporaneously C. Hanseni on specimens from Idothea 

 kalthica from Denmark and C. Meinerti on specimens from Synidothea nodulosa Kr. from West Green- 

 land and Jugor Schar; they had received the material from the Copenhagen Museum. They described 

 the females of both species and the male of C. Hanseni, but did not mention the male of C. Meinerti. 

 Some specimens of 51 nodulosa with the parasite from West Greenland arc to hand, and the male shall 

 be described presently. But, before doing so, it may be stated that I have found a female with male 

 of the same parasite in the marsnpium of the specimen of Plturoprion Murdochi Ben. mentioned 

 on p. 196. 



The differences between the females of the two species of Clypeoniscus have been pointed out 

 by the French authors, and the female from Pleuroprion agrees well with their figs. 2021. I think, 

 however, that this would scarcely suffice for referring the parasite on Plturoprion to the same species 

 as that on Synidothea^ but the males agree closely and, besides, differ sharply in an easily observed 

 feature from the male of C. Hanseni; therefore I am forced to refer the parasite on Pleurofrwn Mur- 

 dochi to C. Meinerti. 



Giard & Bonnier published a large and good figure (PI. IX) of the male C. Hanseni, and in 

 1899 Sars published several figures of another Danish specimen. When comparing my figure of the 

 head of C. Meinerti (fig. 17 a) with the figures of C. Ilanseni referred to, it is instantly seen that the 

 first joint of the antcnnulx* of C. Meinerli differs much in shape and size from the same joint in 



