CycUdina.} THE INFUSORIA. 241 



C. glaucoma would rank under Oxy trichina. Transverse 

 self-division is very common, but longitudinal has not yet 

 been observed. The female sexual apparatus is unknown, 

 but a large round gland is seen in C. glaucoma and 

 C. lentiforme. 



357. CYCLIDIUM glaucoma (M.) The blueish Cyclidii 

 have an oblongo-elliptical body ; the abdomen is margi- 

 nated with cilia, and delicate longitudinal striae are ob- 

 served upon the back. In swimming, they resemble 

 Gyrinus, or Notonecta, a well-known little black water- 

 beetle (see Microscopic Cabinet, plate iv.), which swims 

 in flocks, glancing like silver upon the surface of the water 

 of shady ditches. Sometimes the movement is very quick ; 

 at other times the animalcules remain stationary, and then 

 spring with a curvetting motion to another spot. Formerly 

 this species was confounded with G. scintillans; but the 

 latter is much larger. Fig. 209 (plate iv.) is a side-view, 

 shewing the cilii; ^7. 211 a dorsal view ; and fig. 210 a 

 specimen undergoing transverse self-division. They are 

 represented as fed with indigo. Abundant in vegetable 

 infusions in the spring. Length l-2880th to 1-1 150th. 



358. CYCLIDIUM margaritaceum. The pearl Cyclidium. 

 Body orbicular, elliptical, the posterior end slightly 

 excised ; the dorsal surface has distinct longitudinal lines, 

 the cilii are not distinct. Length 1-1 500th to 1- 1000th. 



359. CYCLIDIUM (?) planum. The flat Cyclidium. Body 

 oblongo-elliptical, smooth ; cilii but little marked. Size 

 1 -2640th. 



360. CYCLIDIUM (?) lentiforme. The lenticular Cycli- 

 dium is smaller than the preceding, and has no distinct 

 striae or cilii < Size 1-3 180th. 



R 



