ORDERS AMONG ANIMALS. 235 



Oken and the physiophilosophers generally have taken 

 a different view of orders. Their idea is, that orders re- 

 present, in their respective classes, the characteristic fea- 

 tures of the other types of the animal kingdom. As 

 Oken's Intestinal or Gelatinous animals are characterized 

 by a single system of organs, the intestine, they contain 

 no distinct orders ; but each class has three tribes, corre- 

 sponding to the three classes of this type, which are Infu- 

 soria, Polypi, and Acalephs. The tribes of the class of 

 Infusoria are Infusoria proper, Polypoid Infusoria, and 

 Acalephoid Infusoria ; the tribes of the class of Polypi are 

 Infusorial Polypi, Polypi proper, and Acalephoid Polypi ; 

 the tribes of the class Acalephs are Infusorial Acalephs, 

 Polypoid Acalephs, and Acalephs proper. But the classes 

 of Mollusks, which are said to be characterized by two 

 systems of organs, the intestine and the vascular system, 

 contain each two orders, one corresponding to the Intes- 

 tinal animals, the other to the type of Mollusks ; and so 

 Acephala are divided into the order of Gelatinous Ace- 

 phala and that of Molluscoid Acephala, and the Gastero- 

 pods and Cephalopods in the same manner into two 

 orders each. The Articulata are considered as repre ; sent- 

 ing three systems of organs, the intestinal, the vascular, 

 and the respiratory systems; hence their classes are di- 

 vided each into three orders. For instance, the Worms 

 contain an order of Gelatinous Worms, one of Molluscoid 

 Worms, one of Annulate Worms, and the same orders are 

 adopted for Crustacea and Insects. Vertebrata are said 

 to represent five systems : the three lower ones being the 

 intestine, the vessels, and the respiratory organs, and the 

 two higher the flesh, (that is, bones, muscles, and nerves), 

 and the organs of the senses; hence, five orders in each 

 class of this type, as, for example, Gelatinous Fishes, Mol- 



