336 Frits Johansen. 



large as the head of a pin, in colour sometimes whitish yellow — 

 pale-red, sometimes orange yellow — purple red (the body, especially 

 the spaces between the legs, is coloured most) and with blue-black 

 frontal eye. The large lateral eyes are still wanting, and the tail 

 spines are quite short, as also the carapace. On the other hand, 

 the swimming palps (the second pair of antennæ) are very long 

 in comparison with the whole animal and play an important 

 part in movement, like the feet which are already present. It is 

 difficult to catch sight of these young, as they mostly keep among 

 the herbage on the bottom by the banks, under stones and the like; 

 the newly hatched young are to begin with not very lively, but 

 often only move themselves when they are stirred up. Further, by 

 comparison with the young of Daplmia and the Ostracods they are 

 very few in number and are found almost exclusively in sheltered 

 corners, where there are collections of the green thread-algae and 

 the small animals living among these — so that it was just a chance 

 vnth specially good fortune that I was able on the whole to find 

 them. Their mode of progression is extremely characteristic and 

 pleasant to watch, as I have found on keeping them in a glass with 

 water; they are very delicate, however, and much less tenacious of 

 life than the Daplmia and Ostracod-y oung. If they are lying on the 

 bottom, searching through this as the adults do, they may suddenly 

 be seen rising with long strokes until they reach the surface. Under 

 this they hang as a rule vertically with the tail bent a little in to- 

 wards the underside of the body, and they swim almost entirely by 

 means of the long palpi. With the latter they all the time make 

 uniform and equal strokes of definite duration; and each time they 

 advance they slip a little backwards. The moл'ement reminds one 

 to a great extent of that of a watch-spring; so long as it is going 

 the movement proceeds regularly. Owing to the great amount of 

 flexibility of the body and tail, these small animals can easily make 

 all sorts of twistings and turnings, as somersaults etc., as they may 

 suddenly instead of the regular, vertical hops throw themselves 

 horizontally through the water; or they may roll themselves up and 

 head first seek down to the bottom, shutting up the palpi under the 

 carapace and moving by means of the foliaceous legs. 



In the middle of July the metanauplii are no longer met with; 

 but we now find somewhat larger, though small fry, which with 

 exception of the short tail spines quite resemble the adults (also in 

 colour), and they also occur at the same places. Sometimes we 

 only notice them after taking some of the full-grown up out of the 

 water (the latter, namely, are already common from the end of 

 June, coming probably up out of the mud or in towards the banks 



