ATTEMPT TO RE-CLASSIFY THK ROTIFERS. 



341 



of Microcodon clavus crowns a rounded ganglion covered 

 with purple segments; and, in all the cases which I have been able 

 to investigate, the eye-spots are either seated on the principal 

 nervous mass, or have nerve-threads passing to them from it. 



Unfortunately however it often happens that eyes which are 

 conspicuous in the egg, or in the young, become difficult of detec- 

 tion in the adult. This is the case with Stephanoceros (fig. 10) 

 and the Floscules (fig. 11) ; in which genera the eyes of the adults 



Fig. 8. 



Fig. 7 



BracJiionus amphiceros. 



Triarilira 

 longiseta. 



Fig. 7. — a. Principal ciliary wreath. e. Eye. /. Mastax. ff. (Esophagus. 



h. Gastric gland, i. Salivary gland, j. Stomach, m. Convoluted tubes. 



n. Contractile vesicle, o. Ovary, q. Muscle, r. Foot. 

 Fig. 8. — a. Principal ciliary wreath, b. Secondary ditto, c. Antenna. /. 



Mastax. g. (Esophagus, h. Gastric gland, j. Stomach, k. Intestine. 



/. Anus. 0. Ovary, p. Ovum. 



are best seen by treating them as opaque objects, and throwing 

 a strong light upon them from above. Moreover, there are 

 often red spots on Rotifers which are not eyes at all ; so that 



