031 DESCRIPTION OF [Rotatoria 



MoxocERC.v jmrcellus. — Body thick and plump ; foot short, much 

 curved and bent under the body, dilated, flattened horizontally, and 

 carrying a smaller spine beneath it as in a sheath ; front and chin each 

 armed with a short sharp spine. Length, including foot, 1-llOth. 



M. sti/Iafa. — Body short, irregularly oval ; foot a nearly straight 

 spine, less than one third of total length ; eye large, red, set like a 

 wart on the back of the occipital sac ; forehead conical, pointed. 

 Length, including foot, l-170th. 



Genus Notommata. — The neck-eyed Rotatoria have a single eye 

 upon the neck, a bisulcate foot, resembling a forked tail. The 

 I'otatory organ compound, its cilia forming in bundles on the frontal 

 region ; eight of the larger species have numerous muscles ; eighteen 

 or nineteen have two jaws, each furnished with a single tooth ; in 

 eight the jaws have many teeth ; the oesophagus is mostly short, 

 with a simple wide conical alimentary canal {coelogastrica) ; in N. 

 tuha only is there a stomach-like division, with a constriction 

 ((/asterodeIa,a), and inN. myrmeleo, N. syrinx, and N. clavulafa, 

 there is also a stomach-like enlarged place, but no constriction 

 {gasterodeJa, h) ; caecal appendages are observed only in N. clavulata. 

 The two earlike anterior appendages of the alimentary canal, re- 

 garded as pancreatic glands, exist in twenty-four species. The 

 propagative system, says Ehrenberg, is hermaphroditic in sixteen 

 species ; in the others the ovarium only is seen : none are vivi- 

 parous : N. syrinx alone ^was observed by Ehrenberg to contain 

 fully developed ova. The vascular system is represented, in ten 

 species, by delicate tubes, with flexible and tremulous gills; only 

 three of the smaller species have gills : in N. myrmeleo and N. syrinx, 

 a broad vascular network is distinct about the head : a prominent 

 respiratory (?) tube in the neck is present in four or five species ; 

 in some others an opening alone is seen. The visual point is red, 

 except in N. felis, where it is colourless ; a ganglion is placed 

 beneath the eye in twenty-six species. In N. cojjeus and N. cent- 

 riira, the brain is three-lobed, and placed over the oesophageal head; 

 in the rest it consists of one or more nervous ganglia, situated 

 amongst the ciliary muscles of the frontal region ; free nervous 

 threads and ganglia are also observed in different species. This 

 genus is especially remarkable for the parasitical habits of its members. 



