380 ON THE ORIGIN OF ENTUZOA 



of assigning to them nearly the last place in the chain of I 

 animal existence, as we proceed from man, the most perfect and 

 complicated organism, downwards. Cuvier has placed them 

 in the second class of Zoophytes, and has included with them 

 several external species. According to his arrangement, we 

 liave them divided into the Cavitaires, or those which have an 

 abdominal cavity and a distinct intestinal canal ; and the 

 Parenchymateux, or those in which no proper intestinal tube 

 is evident, and which, for the most part, possess a homo- 

 geneous structure. 



This arrangement of Cuvier's is, however, unnatural, seeing 

 that worms, most dissimilar in appearance, round, flat, and 

 globular, are here promiscuously associated. The classifi- 

 cation of Goeze is perhaps the most natural, (although far 

 from perfect,) and it is that which Rudolphi has embraced — 

 substituting classical names for German ones. The following 

 are the orders. (See Rudolphi.) 



1. Nematoidea — {vijjxa, a thread, and tidog, form) vermes teretes; 

 Rimdwurmur of Zeder. 



2. Acanthocephala (anavda, a thorn, and Ke<pa\r], the head) vermes 

 uncinati ; Lakenwiirmur of Zeder. 



3. Trematoda (rptjfxa, a foramen) ; vermes suctorii; Sangwurmur of 

 Zeder. 



4. Cesloidea {icitrTOQ, a band, and t'l^og, form) vermes tcenice formes; 

 Baudrvurmur of Zeder. 



5. Cystica {Kvcmg, a bladder) ; vermes vesicular es, Blasenwurmur 

 of Zeder. 



I have not thought it requisite, at present, to enter more 

 fully into a description of this singular class of animals, than to 

 give that general idea of their external characters which the 

 classification of Goeze presents, but hope, at a future time, to 

 avail myself of your excellent Magazine, by giving the results 

 of my examination into the structure of some of them. Perhaps 

 to most persons the title at the head of this paper would 

 convey a correct idea of the object of the inquiry, but lest it 

 should not be explicit to all, I wish to state that I am not 

 about to inquire into the mysteries of worm generation, (for 

 this would indeed be hopeless,) but to confine myself to the 

 question. Whence do they arise ? Nearly all the orders of 

 animals with which we are acquainted are subject to them ; 



