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POPULAR SCIENCE REVIEW. 
the planula is very clearly stated, abundant notes accompanying this part 
of the work, and supplying references to all those sources from which the 
reader may seek further details. Then follows the plan of tabular arrange- 
ment employed in diagnosis. This is an analytical key on the dichotomous 
method — aut Csesar aut nullus — which has been found so useful in the 
identification of species ; the primary division of the groups being, how- 
ever, into two sections, Athecata, in which there is a polypary but tliere 
are no true calycles, and Tliecaplioray in which true calycles are present. 
Those who are already slightly familiar with the Hydrozoa will be glad to 
find that Mr. Hincks’s terminology, while it accords in all essential par- 
ticulars with that adopted b}' Professor Huxley, in his ‘‘Oceanic Hydrozoa,” 
is nevertheless a briefer one. Indeed it consists of about twenty terms in 
all, and these are very tersely defined by the author. The chapter on the 
principles involved in the classification of these organisms is a very careful 
criticism of the views of other writers, and an avowal of the author’s own 
opinions. Here, Mr. Hincks, accepting Professor Greene’s expression of 
Professor Huxley’s method, objects to this, and gives very distinct reasons 
for so doing, and it is curious to observe that the method of classification 
really adopted now by Professor Huxley, is that, or very nearly that, which 
Mr. Hincks proposes. Indeed, the reader who will take up Professor 
Huxley’s work on classification, and compare it with Mr. Hincks’s suggestion, 
will find that in great measure the ideas of the latter have been carried out 
in anticipation. The three orders of Hydrozoa adopted by the two naturalists 
may be thus compared tabularly : — 
Hydrozoa. 
Order -f Siphonophora, Discophora. — Hincks. 
1 Hydrophora, Siphonophora, Discophora. — Huxley. 
We have one word to say in concluding our notice of this beautiful work, 
and that refers to the plates. Two editions of the work have been issued si- 
multaneously : in one, the plates have all the fidelity and artistic excellence 
which was to have been expected from the conjoint labours of Mr. Hincks and 
Mr. Tuffen West ; in the other, a cheaper edition, the plates have been printed by 
what is known as “transfer,” hence the illustrations do injustice to the artist. 
Motives of economy on the part of the publisher, we presume, are to blame 
for thi.s, but we should imagine it was not done with the consent of the 
author. Nevertheless, the illustrations are effective and truthful, and the 
whole book is really above praise. 
VEGETABLE TERATOLOGY.* 
J UST as animal teratology affords us a clue in many difficult questions of 
niorpholog}', so does vegetable teratology afford a key to the laws of the 
homologies of plants. Or at least so it ought to do. Dr. Masters thinks 
• “ Vegetable Teratology : an Account of the principal deviation from the 
usual construction of I’lants.” By Maxwell T. Masters, M.D., F.L.S. Pub- 
lished for the Ray Society by R. Hardwicke, 180U. 
