REVIEWS. 
285 
been just enumerated ; but it is a very difficult matter to say whether the 
seven groups, some of considerable extent, which are massed under the 
present head are rightly associated into one class, or should be divided into 
several.” 
It must not be supposed from what we have said that Professor Huxley 
confines his remarks to the relations and distinctions of the classes. His 
first observations are devoted to these, but he subsequently goes very fully 
into the grouping of the classes into sub-kingdoms, and their division into 
orders. His opinions on the subject of sub-kingdoms are so different from 
those given in the old text-books that we may briefiy advert to them. He 
does not assert arbitrarily that the animal world should be divided in such 
and such a manner, but he states fully, and yet with remarkable concise- 
ness, the characters which lead to conclusions on one side or the other, and 
then modestly expresses the opinion which he himself forms. In this way 
he explains his reasons for splitting up the Articulata into the sub-kingdoms 
Anntjlosa and A^tnuloida, the latter containing the Scolecida and Echino- 
derms: and theMollusca into Mollusca and Molluscoida, the latter embrac- 
ing the Ascidioida,Polyzoa, and Brachiopoda. The Ccelenterata he allows to 
remain nearly as they were established by Frey and Leuckart. But he very 
considerably modifies the old group Protozoa. Professor Huxley thinks that 
the Infusoria, which show some relationship to the Turbellaria, present cha- 
racters which separate them from the sponges in a very marked degree : 
he therefore proposes that they should stand apart as a sub-kingdom. And 
finally he allows the Spongida, Radiolaria, Rhizopoda, and Gregarinida to stand 
together under the old term Protozoa. The sub-kingdoms into which he 
groups the animal world would therefore be — arranging them in Professor 
Huxley’s fashion — as follows : — 
Vertebrata 
Mollusca Annulosa 
Molluscoida Annuloida 
Ccelenterata Infusoria 
Protozoa. 
The author makes no assertion as to the equivalency of these groups. His ob- 
ject has been rather to show in what way existing knowledge justifies us in 
arranging the animal classes, than to lay down a constant andpermanent system. 
In one thing we thoroughly agree with him, and that is in believing that the 
old sub-kingdom Badiata is effectually abolished.” Yet it is strange in 
how many lecture-theatres the old Cuvierian classification still fiaunts in 
diagrammatic form on the walls, and how many teachers, in defiance of the 
intelligence of their pupils, cling to the barbarous omnium gathei'um it ex- 
presses. Professor Huxley has done much to bring about its effectual 
abolition, and we think that the excellent volume before us places it 
for ever hors de combat, by indicting on it the coiip de grace of a keen power 
of logical argument and an impartial observation of established fact. ^ 
