512 DESCEiFTioN OP {^Polygastrtca. 



rani among the Oxytrichina. Transverse self-dmsion 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. 



CxciiDivM glaucoma (M-) — Body oblong-elliptic, abdomen fringed with 

 cilia, and delicate longitudinal striae are observed upon the back. In 

 swimming, they resemble Gyrinus, or Notonecta, a well-known little 

 black water beetle (see Microseo^nc Cabinet, plate 4), 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 for a while stationary, and then presently spring 

 with a curvetting motion to another spot. Formerly this species was 

 confounded with Gyrinus scintillans ; but the latter is much larger. 

 (P. 4, f. 209 is a side view, showing the cilia; fig. 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. 



C. margaritaceum. — Body orbicular, elliptical ; the posterior end 

 slightly excised ; the dorsal surface has distinct longitudinal lines, 

 the cilia not distinct. Length 1-1 500th to 1-lOOOth. 



C. (?) planum. — Body oblong- elliptic, smooth ; cUia but little 

 marked. Size 1 -2640th. 



C'. (?) lentiforme is smaller than the preceding, and has no distinct 

 strite or cilia. Size 1-3 180th. 



Genus PANTOTEicntrM. The muff Animalcules. — Body turgid, 

 covered with moveable cilia. In P. JEnchelys stomach-cells are dis- 

 tinctly visible. Ova are not satisfactorily seen, though the green 

 colour of P. vohox, and the yellow-coloured matter of the other 

 species, probably indicate their presence. jEhrenberg says, " the 

 absence of a double opening is not yet proved, nor, on the other 

 hand, is its existence." 



P. Enchelys. — Body cylindrical, oblong, rounded at both ends. It 

 is of a pale yellow coloiu', but hyaline at the two extremities, and 

 turbid at the centre. Fig. 212 is a cluster of animalcules; those to 

 the left, are more highly magnified than the others. In swimming 

 they I'evoh'c and glide along in the diiectiou of the longer axis of 

 the body. Found in inl'usions of raw flesh. Length l-1150th. 



