PHYSIOPHILOSOPHICAL SYSTEMS. 343 



The principle of the subdivision of the classes among Invertebrata is here 

 exemplified from the Radiata (Echiuoderrnata). Each series contains three 

 orders. 



1st Series. 2nd Series. 3rd Series. 



Evolutio prievalens Evolutio prtevalens Evolutio pnevalens 



systematic digestiouis. systematis circulatiouis. systeinatis respirationis. 



ASTEROIDEA. EcHINODEA. SCYTOBEEMATA (Holo- 



thurioids). 



1. Eucrinoidea. 1. Aprocta. 1. Syuaptoidea. 



2. Comatulina. 2. Echinina. 2. Holothurioidea. 



3. Asteriua. 3. Spatangoidea. 3. Pentactoidea. 



In Vertebrata each class has five series, and each series three orders ; so 

 in Mammalia, for example : 



1st Series. 2nd Series 3rd Series. 



Evolutio prtevalens Evolutio prxvalens Evolutio prsevalens 



sensus tactus. sensus gustus. sensus olfactus, 



CETACEA. PACHYDEKMATA. EDENTATA. 



1. Balanodea. 1. Phocina. 1. Monotrernata. 



2. Delphinodea. 2. Obcsa. 2. Lipodonta. 



3. Sirenia. 3. Ruminantia. 3. Tardigrada. 



4th Series. 5th Series. 



Evolutio prtevalens Evolutio prajvalens 

 sensus auditus, sensus visus. 



UNGUICTJLATA. PRIMATES. 



1. Glires. 1. Chiropteri. 



2. Bruta. 2. Heinipitheci." 



3. Ferae. 3. Anthropomorphi. 



Instead of considering the orders as founded upon a 

 repetition of the characters of higher groups, as Oken 

 would have it, Fitzinger adopts series as founded upon 

 that idea, and subdivides them further into orders as 

 above. These series, however, have still less reference to 

 the systems of organs which they are said to represent, 

 than either the classes or the higher divisions of the ani- 

 mal kingdom. In these attempts to arrange minor groups 

 of animals into natural series, no one can fail to perceive 

 an effort to adapt the frames of our systems to the impres- 

 sion we receive from a careful examination of the natural 



