22 G. O. Sars. 



the head is perfectly straight and horizontal, whereas the 

 upper one is obliquely ascending- and, but very slightly 

 convex. 



The antennulæ, which issue from the most anterior part 

 of the head, are greatly developed, being fully as long as 

 the head. They are very mobile, but, as a rule, extended 

 obliquely anteriorly, with the terminal part more or less 

 incurved (see fig. 7). Near' the base they each form a some- 

 what genicular bend, and at this place 2 unequal sensory 

 bristles are seen to project anteriorly. The outer part of 

 the antennulæ is rather narrow, and nearly cylindric, and 

 terminates with 4 strongly curved hooks, between which a 

 small bundle of olfactory papillæ is traceable (see fig. 8). 



The 1st pair of legs (fig. 9) are, as usual, transformed 

 into powerful grasping organs. They closely resemble in 

 structure those in the male of M. paradoxa, as figured by 

 Prof. Weismann, each having a rather long, setiform appen- 

 dage extending beyond the claw, and terminating in a fine 

 hooked point. In addition, a thin lamella is seen projecting 

 inside the claw, having 3 apical bristles, the anterior of 

 which is curved in a hook-like manner, and devoid of cilia. 



The tail does not seem to differ essentially in structure 

 from that in the female. 



The testes (see fig 6 & 7) are confined to the posterior 

 part of the trunk, appearing as 2 somewhat twisted bags, 

 which extend along the sides of the intestinal tube. They 

 are each continued into a narrow duct, which enters the 

 tail, and debouches at the sides of the anal orifice. Viewed 

 by a high magnifier (fig. 10), they are found to be filled 

 with clear rounded cells, very densely accumulated in the 

 anterior, dilated part of the bags. It often happens, when 

 a male specimen is examined for any length of time under 



