1893. SOME NEW BOOKS. 149 
appendages, doubtless sheathed in true horn during life; several of 
the upper premolars were as complex as the molars, the incisor teeth 
were reduced in number or wanting, and the femur had nearly lost 
its third trochanter. Dzuplacodon, of the upper or Uinta Eocene, forms, 
however, as might have been expected from its geological horizon, a 
perfect connecting link between 7itanotherium on the one hand and 
Palgosyops and its allies on the other. In this genus the skull has 
no horn-like appendages, while only the last of the upper premolars 
resembles the molars, and the typical three pairs of incisors are 
retained. 
The evolutionary development of the Palgosyops-Titanotherium line 
may, therefore, now be regarded as worked out as fully as that of 
the Rhinoceroses, and it is curious to notice how closely the two groups 
follow parallel courses in this respect. Thus, in both there has been 
a development of horn-like appendages to the skull; in both the pre- 
molars have tended to assume a molariform structure, while in both 
the last upper molar has more or less completely lost the hinder 
of its two inner columns; then, again, the more specialised forms 
in each group have the front of their jaws edentulous. On the other 
hand, while the most specialised Rhinoceroses have acquired high- 
crowned (hypsodont) molar teeth, and have reduced the number of 
digits on the fore-limb from four to three, the Titanotheres have still 
low crowned retained the (brachyodont) molars and tetradactylous fore- 
feet of their Eocene ancestors. 
So far as we can gather from his memoir, Mr. Earle seems to 
consider that the unguiculate Chalicotherium, in spite of the similarity 
in the structure of its molar teeth, has no sort of affinity with Pal@o- 
syops and Titanotherium. This, however, we are not at present pre- 
pared to admit. 
THE STUDENT’s HANDBOOK OF PHysIcAL GEoLoGy. By A. J. Jukes-Browne, IB TAG, 
F.G.S. 2ndedition. Pp.666. London: George Bell & Sons, 1892. Price 7s. 6d. 
Tue new edition of Mr. Jukes-Browne’s Handbook is too bulky, and 
would be improved by judicious compression. We would suggest, 
for instance, that it is quite unnecessary to say so much about the 
internal state of the earth, considering how little is known, and how 
likely to mislead is an appearance of knowledge. Already the dogmas 
of the rigidity of our globe and the stability of the earth’s axis have 
been rudely shaken, and even the mathematicians hesitate. Is it 
really necessary, also, to ask the unfortunate student to master such 
terms as metatvopy, metataxis, and metacrasis, and to understand what 
they mean? No examiner is likely to expect a knowledge of a 
number of technical expressions which he does not himself use, and 
which are not current coin. 
We draw attention to these slight imperfections, for it is evident 
that the book meets a want, and will have an established place as a 
class-book for students, if it can be kept within reasonable limits as 
to size and price. 
ATLAS DES ALGuES Marines. By Paul Hariot. Pp. 51. 48 Plates. Paris: 
Klincksieck, 1892. Price 12 francs. 
Tuis volume of the Librairie des Sciences Naturelles aims at guiding the 
young phycologist to a knowledge of the more common seaweeds. 
On the 48 plates there are represented 110 species (not 108 as stated 
on the title-page), easily collected on the shores of France, and, with 
