DESCRIPTION OF THE PLATES. 127 



PLATE VIII. Fig. 2. The anterior extremity and suctorial mouth of 



Neuronaia Monroii more highly magnified. 

 Fig. 7. The cyst of Neuronaia Monroii in a bundle of ner- 

 vous filaments. The fissured appearance of the 

 cyst, with its epithelia, are represented in this 

 drawing. 



I am inclined to believe that the function of 

 the cyst in this and the other Cystic Entozoa is 

 to supply nourishment to the enclosed animal, 

 drawing it from the surrounding parts, and 

 throwing it into the cavity, the structure and 

 action being identical with that in the encysted 

 tumours, as already described. 



The bulbous extremities of the cysts of Tri- 

 china spiralis contain masses of germinating cells, 

 to which I am inclined to attribute the same 

 function. 



Fig. 8, 9, 11. The clavate extremities of the cysts of Tri- 

 china spiralis, with their germinating absorbent 

 cells. 



The epithelium and absorbent cells of the 

 cysts of the entozoa may be considered as per- 

 manent yelk-cells, in the economy of these per- 

 sistent embryoes. 



Figs. 1, and 3. Magnified drawings of Sarcena Ventriculi 

 described, but badly figured by me in the Edin- 

 burgh Medical and Surgical Journal, No. 151. 

 I am still of opinion, notwithstanding the argu- 

 ments of Mr. Busk, in the Microscopical Journal, 

 that this body is a vegetable parasite, its sudden 

 occurrence and sudden disappearance being 

 not more extraordinary than the rapid develope- 

 ment of many cellular structures ; the glandular 

 epithelium, for instance, during secretion. That 

 it is a Gonium, as has been suspected by 

 Professor Link, appears to me improbable, as 

 would be admitted, I believe, by that great 

 botanist, if he had had an opportunity of ob- 

 serving its peculiar vegetable aspect, so dif- 

 ferent from that of an infusorial animal. 



