WHEEL-BEARERS 



leans over considerably to the right side. Its basal por- 

 tion is hollow, and is continuous with the general cavity 

 of the shell, for we sometimes see portions of the viscera 

 in its interior. 



The head of the animal is rounded, and divided into 

 several blunt eminences or lobes, which are set with cilia; 

 these rotate constantly, but irregularly and feebly, and do 

 not make manifest wheels, as Brachionus does. A small 

 antenna projects from the back of the head, capable of 

 being erected or inclined. A long brain descends along 

 the base of the ridge, carrying a bright and rather large 

 crimson eye set like a wart on its interior angle. 



Instead of the flexible and contractile foot of Brack- 



ionus, the Whiptail has a single horny spine of great slen- 

 derness, and exceeding in length the whole body. This 

 spine probably represents not the foot, but one of the toes 

 at the end of the foot. For it is attached to a very short 

 foot, in the midst of two or three bract-like spines, one 

 of which, longer than the rest, and distinctly movable, 

 probably represents the other toe undeveloped. The 

 long spine is set on by a proper joint, a globose bulb 

 being inserted into a socket, which allows it free motion, 

 in all directions except backward. The socket itself is 

 contained in a second joint, the basal part of which is in- 

 serted at some distance within the aperture of the lorica. 

 This articulation is formed by an infolding of the skin, 

 but is permanent in its position. 



