LESSON 31.] 



NUTRITION IN ACALEPHA. 



107 



FIG. 181. 



covered. Some sting and inflame the hand that touches them ; but 

 the cause of this power is equally unknown." 



524. Our ignorance of these animals is by no means so profound at 

 the present day, albeit much yet remains to be discovered. John Hun- 

 ter was the first to inject the stomach and communicating canals, and 

 thus discovered the extraordinary route by which the nutriment 



reaches the digestive cavity, and also 

 the channels by which the digested 

 aliment is distributed for the sup- 

 port of the general system. 



The animal on which the expe- 

 riment was made, belonged to the 

 Genus Ehizostoma (rhizoma, a root ; 

 stoma, a mouth), and a figure of it 

 is appended (Fig. 181). 



525. Every part of the body of 

 this Bhizostoma Cuvieri is of the 

 utmost transparency, so that the 

 internal organs may be distinctly 

 seen through the external parietes 

 of the mantle. 



The gastric cavity, or stomach 



(d)j is in the centre, surrounded by four ovarial sacs (e, e, e). A 

 number of wide vessels extend from the circumference of this quad- 

 rangular stomach to the pur- 

 ple-colored, highly vascular, 

 lobed and respiratory margin 

 of the disc (Figs. 181 and 

 182, h, h). 



The peduncle hangs sus- 

 pended from the centre of 

 the disc, and is divided into 

 eight branches (c, e), which 

 terminate in simple lobed di- 

 latations (a, a), having their 

 surface marked with numer- 

 ous depressions, which are the 

 orifices of internal canals (a, 

 5, c), leading upwards to the 

 stomach (d). In the middle 

 and upper parts of these section of EMzostoma. 



FIG. 182. 



