ZOOLOGICAL DIAGRAMS. 95 



grade of development) may be referred. The names of these types are as 

 follow : — 



1st. Vertebrata — which may be divided into two sections, the first, 

 M Abranchiata," including mammals, birds, and reptiles ; the second, 

 " Branchiata" — amphibians and fishes. 



2nd. Mollusca, divided into two groups — 1st, true mollusca, and 

 2nd, molluscoida. The last division includes the brachiopods (?), tuni- 

 cates, and polyzoa. 



3rd. Annulosa, which also is separable into two groups — 1st, true 

 annulosa, which includes insects, myriapods, spiders, and crustaceans ; 

 2nd, annuloida, comprising echinoderms, annelids, rotifers, and the flat- 

 bodied and nematoid worms. 



4th. Ccelenterata, including zoophitic and acalephoid forms. 



5th. Protozoa. — In this division are placed the sponges, rhizopods, and 

 true infusoria. 



In certain matters of detail this classification is, no doubt, imperfect. 

 Thus, the true position of the echinodermata is still a matter of uncertainty. 

 But, on the whole, it gives us the best general expression of the views of 

 modern zoologists which the present state of science is capable of afford- 

 ing. 



We are now in a position to estimate the merits of the arrangement 

 which Mr. Patterson has adopted in his diagrams. The first great error 

 that we meet with is that Mr. Patterson completely ignores one of the 

 most important conclusions which the united labours of many recent 

 researches have established, namely, that two types of organization are 

 included under the radiata of Cuvier (i.e., the last two types in the classi- 

 fication above given). 



At page 45 of the " Explanation" we are informed that the radiata are 

 arranged in six classes : Echinodermata, Acalepha, Zoophyta, Entozoa, In- 

 fusoria, Foraminifera, and Amorphozoa, are the names of the classes given. 

 Any child would say that seven classes are here mentioned ; but on turn- 

 ing to the diagrams themselves we find an explanation of this apparent 

 anomaly ; for the Echinoderms and Acalephs are included together under 

 one class, termed " Radiaria," a name which is employed with the same 

 signification in the " Zoology." We cannot congratulate Mr. Patterson 

 on this original arrangement. The slight external resemblance between 

 some of the medusa and star fishes is surely insufficient to justify any such 

 near association of these animals, as Mr. Patterson proposes. 



The only allusion to the affinity of the zoophytes with the acalepha is a 



