142 The American Naturalist. [February, 
idea of his author. A comparison of the two works is difficult. For 
the student who has already a good foundation in the broader features 
of general embryology, possibly Mark’s Hertwig will prove the more 
useful, for it gives more the broader features of ontogeny without pay- 
ing great attention to minor and, for him, unimportant detail. Minot’s 
work, on the other hand, from its method of treatment, may be better 
adapted for the student of medicine, for it takes up the subject morein 
accordance with the ideas which he receives from the rest of his special 
training, and in those points which may prove of value in questions of 
medical jurisprudence it gives a fulness of detail which is foreign to 
the purpose of the other work. Yet the average practitioner will 
probably have little to do with either volume. All that he cares to 
know concerning the questions discussed, would occupy very few 
pages, and the 670 pages of Mark’s Hertwig, and the over 800 in 
Minot’s volume, will, we fear, scare away the very men who most need 
the information they contain. Yet it is difficult to see how the matter 
could be much more condensed. ‘The fault is not, in either case, with 
the author, but rather with the extent of our knowledge. This, how- 
ever, will prove no drawback for the student of morphology, and, we 
doubt not, these will be two of the most consulted books in his library, 
for they are the two most important additions in our language to the 
literature of biology for the year 1892. 
To conclude, we would say that both books are valuable, and should 
be owned by all morphologists. Minot’s volume is possibly the better _ f 
adapted from its arrangement for the physician, and the greatest 
objection which we can see to its use by medical men is its size. 
Geological Survey of Texas, 1891.’—This volume constitutes 
the Third Annual Report of the Geological Survey of Texas. It com — 
sists of the usual introductory statements of the State Geologist, E. T. 
Dumble, followed by the several reports of his assistants. The accom — 
panying papers are reports on the geology and paleontology Eo 
important regions by specialists in those departments. Mr. Kennedy a 
contributes the result of investigations which carried him across the . 
post-cretaceous deposits, from Terrell, in Kaufman County, in a south- = 
easterly direction to the mouth of the Sabine River. Mr. Cummins — 
gives a detailed report on the geology of the Llafio Estacado. He r 
traced the Carboniferous formation to its farthest outcrop in Central , 
SS he Sea 
eS So 
Texas, determined the northern extension of the Cretaceous along the 
"Third Annual Report of the Geological Survey of Texas, 1891. E.T 
Dumble, State Geologist, Austin, 1892. 
