73 
I 
I II. On Corophium Bonelli (M.-Edw.?) G. O. Sars 
and other species of the genus. 
By K. Stephensen. 
‘ During the winter of 1922—23 my friend Mr. Hj. Ussing of Ran¬ 
ders sent me for determination the material of C. Bonelli, the bio- 
logy of which he has worked out in his preceding paper (p. 69). 
By means of G. O. Sars’s excellent work on the Crustacea of Nor- 
way it was very easy to determine the $ ; but of the ^ there 
( does not exist any drawing in the literature, in spite of its being 
, very characteristic. 
The results of my investigations will be given below. 
Three species are very often confused in the literature from 
, of old viz, C. acherusicum Costa, C. Bonelli M.-Edw. and C. cras- 
I sicorne Bruzel., although the last named species is very easily 
I recognizable: the $ with its very broad 2. antennae, and both 
j sexes with the acute lateral lobes of the head (see Sars 1895, PI. 220). 
It is much more difficult to distinguish the two remaining 
j species from each other. 
On Corophium Bonelli (M.-Edw.?) G. O. Sars 
and C. acherusicum Costa. 
From the literature it is not clearly seen whether these two 
species are identic or not. In order to have this made clear I in- 
• vestigated the material of Corophium in our Museum; I beg to 
acknowledge my most sincere thanks to Dr. Louis Fage of the 
Muséum National d’Histoire Naturelle, Paris, for having kindly 
sent me some specimens of C. acherusicum from France and Algérie, 
determined by Dr. Ed. Chevreux. Chevreux has 1910, p. 271 given 
characteristics of the two species and considers them good species. 
But the characters which he mentions, seem (according to invest- 
igation of my material) to be varying in a rather high degree. I 
have replaced these characters by others which would seem to be 
better: $ has in C. Bonelli on the underside of 4. peduncular 
joint of ant. 2. only one spine (Sars 1895, PI. 221, fig. la-), in C. 
acherusicum there are two spines (Della Valle 1893, PI. 8 fig. 31). 
