36G Mr Henry Goodsir on some New Crustaceous Animals 



Boeckii of Kroyer is the only other species of this genus 

 known.* 



SECTION II. ON THE GENUS EVADNE. 



The next animal to be described is a Daphnoid Crustacean ; 

 it is the Evadne Nordmanii of M. Loven. 



About the end of June and the beginning of July last 

 (1842), innumerable shoals of species belonging to this genus, 

 with immense numbers of ^yz^owos^rac^ws Crustaceans, ranging 

 under the order Copepoda of Milne Edwards, appeared at the 

 mouth of the Firth of Forth. These shoals were most nu- 

 merous about the sheltered parts of the island of May. And 

 so abundant were they, that by drawing a scum- net once 

 through the water, the animals could be taken out of it in 

 handfuls. 



Altliough I have observed one or two undescribed species 

 amongst those specimens which I have got, I have not been 

 able, from want of time, to examine them minutely. In the 

 meantime, then, I will merely give a short account of the ob- 

 servations I have made on M. Loven's species : — 



Genus Evadne (Loven.) 

 The head not detached from the body; the anterior branch of theanten- 

 noe composed of thrccj and the posterior branch of four, articulations. 



Ev.dne Nordmannii. Plate YI. fig. 15. 



Description. — The whole animal almost colourless, except the posterior 

 portion of the eye, which is black ; the anterior portion is much larger, 

 and is deeply ribbed longitudinally. The antenneo are composed of 

 two branches, an anterior and posterior; and a number of long spines 

 arise from the extremity of each. Four short articulated legs arise 

 almost immediately below the eye ; a strong muscle ascends from the 

 legs, and, passing upwards immediately behind the eye, is attached 

 to the dorsal portion of the shell. Each leg is composed of four 

 articulations, and a number of strong spines arise from these articu- 

 lations. All that portion of the internal cavity of the shell, imme- 

 diately behind the muscle, is apparently empty, except during the sea- 

 son of spawning, when this part of the body may be observed filled 

 with ova or young. The posterior part of the body is produced, in the 

 middle, into a strong pointed spine. There is no appearance of an in- 

 testinal canal, and its organism is apparently very simple. Length, 

 half a line. 



« Kroyer. Isis von Oken, 1841; p. 428. 



