52 f- o. SARS. M.-N. Kl. 



The colour of the male is, generally, somewhat lighter than in the 

 female, with a more or less distinct orange tinge, which, especialh^ on the 

 right prehensile anterior antenna is very pronounced. 



Observations. Of this interesting Calanid, some specimens developed 

 in 2 of my aquaria. The}' continued to Yiye during the whole sum- 

 mer, and all the females became at last laden with their egg-bags. But 

 no increase of the specimens took place, and, though in all probability a 

 considerable number of ova were deposited in the mud at the close of 

 the season, this form did not reappear the succeeding vears. 



In habits it agrees with the species of Diaptomus, and mo'V'es in a 

 very similar manner, but the movements are still more abrupt and 

 rapid. Indeed, the broad, fanlike tail in the female, constitutes a most 

 powerful propelling organ, and by a sudden flexion of this part it is 

 enabled to start away so rapidly as to be hardly got sight of. It is, 

 therefore, a matter of no little difficulty to catch the specimens by the 

 usual means, a small dipping tube, and, from this cause, only a small 

 number of specimens were secured for closer examination. 



