Oecistina.} THE INFUSORIA. 335 



is young, and colourless in old age. The ovarium has only 

 a single ova. The lorica is a viscid, gelatinous, cylindrical 

 box (urceolus), into which the animalcule can entirely 

 withdraw itself, or leave, when a new one is desirable. 

 The attachment to the bottom of the lorica is by the under 

 surface of the end of the foot-like tail. 



569. Oecistes crystaUinus. The crystalliue Oecistes. — 

 Lorica hyaline, viscid, floccose ; body crystalline. The 

 structure of this creature is difficult to see. Each jaw 

 has three distinct 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 animalcule came forth. 

 I^?g. 361 represents a full-grown animalcule in the act of 

 unfolding itself; Jig. 362 is another with its rotatory organ 

 expanded. Their shells are incrusted, and within may be 

 seen a number of eggs; Jigures 363, 364, represent them 

 attached to the pectinated leaves of the Mater violet, as 

 they appear under a shallow pocket magnifier. Length, 

 with tail, l-36th; without, 1 -140th: lorica l-70th. 



Genus CXXXIX. Conochilus. The lipped-top 

 Animalcules are social, having conglomerate and con- 

 tiguous lorica ; each animalcule has two permanent eyes. 

 Only one species is known ; its description, therefore, will 

 include that of the genus. 



570. Conochilus volvox. The rolling Conochilus. — 

 The corpuscles are white, their gelatinous lorica is hyaline, 

 within which from ten to forty animalcules unite, and form 

 a radiating sphere, that revolves in swimmino-. The brow, 



