Oecistina] TH E 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 crystallinus. The crystalline 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. 

 Fig. 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; figures 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, 1 -140th: lorica l-70th. 



Genus CXXXIX. CONOCHIL.US. 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 swimming. The brow, 



