50 



LECTURE III. 



Stephaiioceros bichoriiii. 



that part of the respiratory 

 or aquigerous apparatus was 

 the male organ. Most of the 

 Rotifera are oviparous, the 

 ova being large and few^ in 

 number {fig. 22, a.) : the 

 Philodince are commonly vi- 

 viparous. No species has 

 yet been found to be par- 

 thenogenetic, either by way 

 of spontaneous fission or 

 gemmation. 



The egg-forming organ 

 consists of a simple wide 

 sac, single in Notommata 

 {fig. 20, /.), but more com- 

 monly divided into two cor- 

 nua, the body terminating 

 by a short contracted cervix, 

 which communicates with the 

 cloaca. The two other longer 

 and more slender canals con- 

 nected with the cloaca by 

 the medium of the pulsa- 

 tile sac, which are supposed 

 by Ehrenberg to be the 

 testes and seminal vesicle, 

 are the parts already de- 

 scribed as the respiratory 

 system. In the first place 

 Siebold has shown, that 

 in the development of the 

 Rotifera, the long and slender 

 tubes appear and increase in 

 the ratio of the growth of the 

 intestinal organs and before 

 the ovaria ; secondly, they 

 contain nothing but clear 

 liquid ; thirdly, the true 

 nature of the pulsatile sac 

 beiner determined in the Po- 

 lygastria, we may infer that 

 it has to do with the circulat- 

 ing and rcspii-atory process 



