CARPENTER.’S ZOOLOGY. 
113 
of the Brachiopoda, the account of which important class is compressed 
into less than four pages. Their peculiar muscular system is not de¬ 
scribed, nor are the mere names of all the families given. The Tunicata 
likewise are very imperfectly described; the division of this class into 
the two orders, Salpa and Ascidia, being, moreover, decidedly erro¬ 
neous. Many animals of this class, presenting interesting peculiarities 
of structure, are not even mentioned by name. We allude more especially 
to such genera as Doliolum and Appendicularia. To such of our readers 
as have not already made themselves acquainted with it, we would re¬ 
commend the perusal of an excellent paper on the latter genus by Mr. 
Huxley, in the third volume of the “ Microscopical Journal.” In 
accordance with opinions now universally adopted, the Polyzoa are 
placed in the molluscous sub-kingdom. But the student will find few 
of the results of recent researches into the structure and development of 
these forms in the meagre and incomplete survey afforded of the class 
by Mr. Dallas. His classification of the Polyzoa is wrong; his account 
of their development still worse. The peculiar bodies termed ‘ state- 
blasts’ are not spoken of, nor are we told that the Polyzoa possess a 
nervous system. These omissions are the more culpable, since the ad¬ 
mirable monograph of Professor Allman, published by the Bay Society, 
contains a concise, though complete, account of the present state of our 
knowledge of this most interesting class. 
Dismissing the Mollusca, we now turn to the sub-kingdom Badiata. 
We have already, on more than one occasion, given our verdict in favour of 
those naturalists who are of opinion that the name of this group should 
be abolished. The class Echinodermata must for the future be referred to 
the division Annuloida, as has been ably shown by Mr. Huxley; and 
the remaining Badiata will then form a distinct sub-kingdom, Ccelente- 
rata. The dread of interfering too much with a work of which he was 
only the editor may, perhaps, have prevented Mr. Dallas from adopting 
an arrangement not hitherto followed in any elementary manual. He 
divides the Badiata into three classes—Echinodermata, Polypifera, and 
Hydrozoa. The subdivision of the first of these classes here given is 
most incorrect. Many years have now elapsed since Professor E. Eorbes 
clearly showed that the Ophiuridee constituted a distinct and well-marked 
order; and most modern naturalists have viewed them in the same light: 
yet Mr. Dallas continues to unite them, together with the Asteriadae, 
into one order, Steileridae. Again, when we consider that the present 
treatise proposes to describe the chief forms of fossil remains, -no excuse 
can be given for omitting all mention of the two remarkable extinct 
orders, Cystidea and Blastoidea. 
In commencing our brief observations concerning the Coelenterata, 
we are first met by the question, * ‘ Why is the division of this group 
into the two old classes, Zoophytes and Acaleplias, incorrect?” The 
answer is, simply, “ Because it is founded on an anatomical error.” The 
Coelenterata are divided into two natural groups—1st, Hydrozoa; and 
2nd, Actinozoa. In the Hydrozoa the walls of the alimentary canal and 
of the general cavity are almost identical, while the reproductive organs 
