328 ESSAY ON CLASSIFICATION. 



tliis, the types of Mollusca and Articulata (Artliropoda) 

 of the two distinguished anatomists entirely agree. The 

 position assigned by Owen to the provinces Articulata 

 and Mollusca, not one above the other, but side by side 

 of one another, 1 is no doubt meant to express his con- 

 viction that the complication of structure of these two 

 types does not justify the idea that either of them stands 

 higher or lower than the other ; and this is perfectly 

 correct. 



Several groups, established by previous writers as 

 families or orders, are here admitted as classes. His 

 class EPIZOA, which is not to be confounded with that 

 established by Nitzsch under the same name, corresponds 

 exactly to the family called LERNEES by Cuvier. His 

 class HYDROZOA answers to the order HYDROIDA of 

 Johnston, and is identical with the class called DIMORPH^EA 

 by Ehrenberg. His class CCELELMINTHA corresponds to the 

 order of INTESTINAUX CAVITAIKES established by Cuvier, 

 with the addition of Gordius ; while his class STEREL- 

 MINTHA has the same circumscription as the order IN- 

 TESTINAUX PARENCHYMATEUX of Cuvier. Generally 

 speaking, it should not be understood that the secondary 

 divisions mentioned by the different authors, whose 

 systems I have analyzed here, were established by them. 

 They are frequently borrowed from the results obtained 

 by special investigators of isolated classes. But it would 

 lead me too far to enter here into a discussion of all these 

 details. 



This growing resemblance of the modern systems of 

 Zoology is a very favourable sign of our times. It would, 



1 From want of space, I have l>een culata and Mollusca one below the 



compelled, in reproducing the classi- other upon my page; according to 



fication of Owen in the preceding his views they should stand on a 



diagram, to place his provinces Arti- level, side )y side with one another. 



