ERONN S ANIMAL K'TXODOM. Sa-) 



highest forms of the latter do not really occupy a more elevated 

 position in the scale of organization than any Annulose animals, 

 whilst the lowest members of both groups appear to stand in this 

 respect pretty much on a level. 



The great defect in the system adopted in this work is, however, 

 the non-adoption of the sub-kingdom Coelenterata, which may certainly 

 be regarded as well established. The retention of the Eadiated 

 animals (Actinozoa) as a primary group, including botli the Coelente- 

 rata and Echinodermata is manifestly a mistake, and it is clear from 

 Professor Bronn's table that it has given him some trouble to 

 arrange his characters, so that one is surprised that he was not led 

 to separate elements so incongruous. 



After what we have said of the nearly exhaustive mode of treatment 

 adopted by Professor Bronn, it will be unnecessary for us to do more 

 than furnish our readers with a brief exposition of the general classi- 

 fication followed by him. His sub-kingdom Amorphozoa is divided 

 into four classes, of which the Sponges occupy the lowest place. 

 These are followed by the Polycystina, including besides the organisms 

 ordinarily known under that name, the Acantliometrina and Thalassi- 

 collce, the whole of which appear to have been regarded by the author 

 as constituting a group intermediate in many of its characters 

 between the true Ehizopoda and the Sponges. The remaining two 

 classes of Amorphozoa admitted by Professor Bronn are the Bhiso- 

 poda and Infusoria ; the GregarincB 2^ndi Noctilucahemg provisionally, 

 but we believe erroneously, referred to the former group. In his 

 description of the structure of the Poraminifera, the author has 

 availed himself freely of the admirable papers published by Dr. 

 Carpenter in our Philosophical Transactions, but the portion of his 

 work relating to them appeared at too early a date, to allow his views 

 to be influenced by the magnificent volume on those interesting 

 animals issued by the Eay Society. 



With regard to his Actinozoayi\ie author admits the great difference 

 existing between the Coelenterata of Leuckartand the Echinodermata, 

 regarding them as forming two distinct groups {Vnterhreise) ^\ib' 

 ordinate to the great primary subdivision of Actinozoa. He indicates 

 moreover that " the Echinodermata form on the whole a group placed 

 by important characters far above the Coelenterata," but adds, " that 

 a parallel serial arrangement makes its appearance in the classes on 

 each side, inasmuch as their progress to a higher state of organisa- 

 tion is effected, at least partially, by analogous changes," a parallelism 



2 B 2 



