194 NATURAL HISTORY OF ANIMALCULES. 



first, Trachehgastrica, is that in which the creature is 

 destitute of manducatory instruments, and possesses a 

 very long oesophagus, and a simple alimentary canal : 

 this form is illustrated in the Ichthydium (see 182), 

 Chaetonotus maximus, and the Enteroplea. The second 

 kind is the Cologastrica, which Dr. Ehrenberg exem- 

 plifies by the Euchlanis macrura, and the St/nchaeta tre- 

 mu/a: these are furnished with masticating organs, and 

 have a short cesophagus and simple large alimentary 

 canal. The third Dr. Ehrenberg calls Gasterodela : they 

 are in all respects like the preceding, except that their 

 alimentary canal is formed by a constriction into two 

 portions — the anterior or gastric, and the posterior 

 or proper alimentary canal, as in the Enteroplea hydatina, 

 Diglena lacustris, Magalotrocha alba, and in § 419, 431, 

 and 414. The fourth kind, ternied Trachelocystica, and 

 illustrated by the Vorticella rotatoria (395), and Plulo- 

 dina roseala, have a long, narrow^ alimentary canal, sur- 

 rounded by a cellular apparatus : they have also a 

 pharynx and cloacal enlargement. 



In a Supplementary Treatise it is purposed to give a 

 more enlarged systematic arrangement of the Phytozoa, 

 according to their organization, together with the result 

 of such further observations as the Author shall make, or 

 be favoured with, — the design of the present work not 

 admitting it here. 



THE END. 



