612 DESCRIPTION OP {Rotatoria. 



The attacliment to the bottom of the lorica is by the under surface 

 of the end of the foot-like tail. 



Oecistes crystallinus. — Lorica hyaline, viscid, floccose; body crys- 

 talline. The structure it is difficult to see. Each jaw has three dis- 

 tinct teeth. The development of the young from the egg is interesting 

 to observe : Dr. Ehrenberg saw within the shell two dark points 

 (eyes) near the already-developed jaws, and on giving the egg a 

 gentle pressure it burst, and the free young animal came forth. 

 Fig. 361 represents a full-grown animalcule in the act of unfolding 

 itself; fig. 362 is another with its rotatory organ expanded. Their 

 shells are incrusted, and within may be seen a number of eggs ; 

 figs. 363, 364, represent them attached to the pectinated leaves of 

 the water-violet, as they appear under a shallow pocket magnifier. 

 Length, with tail, l-36th; without, l-140th; lorica l-70th. 



Genus Conochilus. — The lipped-top Atmnalcules are social, 

 having conglomerate and contiguous loricse ; each animalcule has 

 two permanent eyes. Only one species is known ; its description, 

 therefore, will include that of the genus. 



C. volvox. — The compound masses white ; lorica gelatinous, 

 hyaline, within which from ten to forty animalcules unite, and form 

 a radiating sphere, that revolves in swimming, like the Volvox. 

 The brow, or frontal region of the animalcule, is broad, truncated, 

 and surrounded with a wreath of cilia, interrupted at the mouth, 

 which is lateral. On the frontal plane arise four thick conical 

 papillae, often furnished with an articulated bristle, especially the 

 two anterior, as seen in figs. 365, 366, and 368. The oesophagus is 

 short and narrow, its head, or bulb, has jaws, with teeth, and four 

 muscles ; it lies immediately within the mouth. The stomach and 

 rectum are oval. Two spherical, pancreatic, or salivary glands, are 

 observed near the oesophagus, and posteriorly an ovarium, often 

 containing a large ovum, which is expelled near the base of the tail. 

 The ovate or shortly-cylindrical body terminates in a long, thin, 

 and strong cylindrical foot-like tail, the end having a suction disc. 

 The gelatinous lorica, is only perceptible in coloured water, except 

 when infested with green parasitical Monads ; within it the animal- 

 cules can completely withdraw themselves, their tails becoming 

 thickened and bent. (In the group, figs. 365 to 368, the lorica is 



