ZOOLOGY. 617 



It is thus evident that the smaller Birds stand below 

 the Aquatics, just as the smaller Thricozoa do beneath 

 the Whales, quite apart from organic structure, which in 

 every respect is imperfect. They must correspond, con- 

 sequently, to the Asarcous animals, wherewith also their 

 great number agrees. 



If this holds good of the two highest classes, so also 

 must it hold good of the two lower, namely, Fishes and 

 Reptiles, and we shall thus have : 



I. Protozooid Fishes, Reptiles, Birds, and Thricozoa. 

 II. Conchozooid "Fishes, &c. 

 III. Ancyliozooid &c. 



IV. Icthyoid 



V. Herpetoid 



VI. Thricozooid 



VH. Ornithoid 



&c. 

 &c. 

 &c. 

 &c. 



3532. But this parallelism depends essentially upon 

 the organs, and they are called, in the language of 

 Physio-philosophy, more correctly : 



I. Intestinal Fishes, Reptiles, Birds, and Thricozoa. 

 II. Vascular Fishes, &c. 



III. Pulmonary &c. 



IV. Osseous &c. 

 V. Muscular &c. 



VI. Nervose &c. 

 Vn. Sensorial &c. 



But as these names are unused, and give or convey 

 only the anatomical idea, but no external image, the 

 first appellations are to be preferred. 



Tenth Class. 



Osteozoa, Glossozoa Pisces. 



3533. No one of the upper classes is in such an 

 extensive state of confusion as that of Fishes. Nor does 

 this result simply from the great deviations in their 

 structure from the normal type, these being rather useful 

 than otherwise for the purposes of classification ; but 

 mainly from the utter want of any principle which might 

 serve systematists as a guide. Thus at one time we 

 find them having recourse to the nature of the osseous 



