1879. ] Recent Literature. 179 
section on Heat as a geological agent, Prof. Comstock’s classifica- 
tion of Igneous and Metamorphic rocks, that on Tertiary mam- 
mals, and the closing section, upon Prehistoric Archeology. But 
the general scope and adaptation of the work are excellent, if its 
purpose be borne in mind; viz., to aid the student in holding to- 
gether the knowledge gained from books and lectures, until in 
the course of time and practice, it can grow up into a connected 
system in his own mind, and become a permanent possession. 
It would be easy to point out things that might be added; but 
were the work enlarged much, it would lose the character which 
it now has, of an “ Outline,” and become what it is not designed 
principal facts and laws of his department, prepared under great 
stress of professional labors at the University, in the sadly vacant 
place of the lamented Hartt. In his preface, he speaks of his 
hesitation, from conscious imperfections, in seeking for the work» 
a wider field than his own lecture room; but he hopes 
still, ae it may prove of service to some other teachers and 
studen He has done well in giving it the possibility of this 
wider ulao and we cannot ‘but think that many will thank 
him for having done so. We would advise any student who 
means to be T and comprehensive, and any teacher or 
professor who would do justice to his work, to procure 
this “Rete book without ‘delay. S. M. 
’ GEGENBAUR’S ELEMENTS OF COMPARATIVE ANATOMY.’—This 
book marks an epoch in comparative anatomy, since the subject 
is not treated in the manner of the older works, such as those of 
Cuvier, Owen, and even Huxley, inasmuch as the facts concern- 
ing the comparative structure of the different organs of animals 
are not presented in a simply comparative manner ascending from 
the mere simple to the complex, but the author goes a step be- 
yond his predecessors, and uses his array of facts as a foundation 
for a theory that may explain why the more complex structures 
have such a constant relation to the simpler. The facts recorded 
in this work are vitalized and interpenetrated by the principles of 
the theory of decent. To some this will be the main fault of 
Gegenbaur’s work, to others, the introduction of a speculative and 
hypothetical thread, weaving all the facts into a connected, logi- 
cal system, will enhance the value of the treatise. At all events 
it is time an effort should be made to combine the facts of com- 
parative anatomy into a harmonious system, and if the hypothe- 
1 Elements of Comparative Anatomy. By CARL GEGENBAUR, Professor of Anat- 
o idleber; K 
JErrrRey BELL, B.A , Magdalen College, Oxford. e Translation revised and a 
Preface written by E. Ray Y LANKESTER, M.A., F.R.S., Fellow of Exeter College, 
Oxford, and Professor of Zodlogy and Comparative Anatomy, in Karmi Saa, 
London: Macmillan & Co., 1878, 8vo., pp. 645. 00. 
