Bntozoa, 



6 ENTOZOA. 



cation wliicli, in some important details, will be found to depart 

 from tlie plans generally in vogue : — 



f Turhellaria 



Sterelmintha ) (Ord. 1). 



(Sub-class I.) i Trematoda 



\ (Ord. 2). 



HELMINTHA ) Ccelelmintha Nematoda 



(Class.) ] (Sub-class II.) (Ord. 3). 



f AcantJiocephala 



Anentekelmintha 1 (Ord. 4). 



(Sub-class III.) J Cestoda 



\ (Ord. 5). 



In this scheme it will be noticed that I have not hesitated, on 

 the one hand, to place the Turbellaria amongst the solid or paren- 

 chymatous helminths {sterelmintha^ Owen ; arepea — e\fj.iv6e<;) ; whilst, 

 on the other hand, I have formed a new sub-class for those hel- 

 minths which are not provided with an intestinal canal {anenterel- 

 mintha ; a — evrepov — ek/u.Lvde'?) J'^ The hollow or cavitary group stands 

 as before (coelelmintha, Owen; kolXt] — e\p,iv6e^). In regard to the 

 first change here proposed, I may remark that the Turbellaria come 

 nearer to the Trematoda than they do to the suctorial annehds ; 

 which latter, be it remembered, are furnished with a complete 

 intestinal tube and anus, and, moreover, their characters, by the 

 intervention of the planarise, are too closely linked on to the Tre- 

 matoda to permit of their being elevated by themselves into a 

 separate class. Yon Siebold, however, has done this, in my opinion, 

 on insufficient grounds ; but it is not unlikely that he would, in 

 opposition to the views here advanced, urge the impropriety of 

 calling the Turbellaria true helminths. In reply, I should be ready 

 to admit that the Turbellaria are not helminths in the same sense as 

 the entozoa, properly so called, but by imparting to the term hel- 

 minth a wider siOTiification than that to which it was restricted 



o 



* Since the above was written, Prof. Leuckart (on stowing him the M.S.) drew 

 my attention to the circumstance that he had some years back employed the term 

 Anenterata to include the Acanthocephala and Cestoda. He referred me to Carus 

 [System der Thierischen Morpholofjie, s. 417), where I find the term in question 

 adopted.— T. S. C. 



