BOOK SIXT. 
TURBELLARIA. 
CLASSIFICATION. ' 
§ 120. 
Tue TuRBELLARIA receive their name from the ciliated epithelium, which 
covers their whole body. Their flattened, or cylindrical, non-articulated 
body, is formed of a loose parenchyma, in ‘which lie hid the viscera. The 
nervous system appears very little developed, and when visible, consists only 
of a cervical ganglion, from which there never extends a ventral cord. 
The multiramose intestinal canal is always without an anus. The genital 
organs are either very much developed, or entirely absent.” In the first. 
case, these animals are always hermaphrodites, and have copulatory organs. 
The Turbellaria have been shifted from one zoological system to another, 
but their organization has sufficient peculiarities to entitle them to a special 
class by themselves. 
Ehrenberg was the first to found the group Turbellaria; but he has in- 
eluded therein many different animals; and we are, jhenstare, indebted to 
Orsted, for a late revision of this group. 
ORDER I RHABDOCOELIL 
The alimentary canal is simple and cylindrical; the cesophagus, non- 
protractile ; locomotion, mostly natatory. 
Genera: Vortex, Derostomum, Gyratrix, Strongylostomum, sMesoetpiaattty 
Typhloplana, Macrostomum, Microstomum. 
ORDER II. DENDROCOELL 
Intestinal canal dendritically ramified; cesophagus completely protrac- 
tile; locomotion reptatory. 
1 I cannot here omit the question, if these small era, and if they are not rather the larvae of other 
sexless Turbellaria, as for example, Derostomum, inferior animals. 
and Microstomum, really constitute distinct gen- 
