488 



SCIENCE. 



[Vol. V., No. 123. 



No one can bring about a great reform, 

 unless in a social medium already somewhat 

 prepared for it. It was Rolleston's good for- 

 tune to work at a time when his efforts were 

 not mere hopeless assaults on a fortress ren- 

 dered impregnable by prejudice. He battled 

 at an epoch when many sympathized with him, 

 and were ready to help. But it is his glory to 

 have been the leader, exceptionally fitted by 

 natural gifts and academic career, to conduct 

 to victory those who desired to widen the 

 range of Oxford studies. To him, more than 

 to any other one man, is it due that in bio- 

 logical teaching the university on the Isis is 

 now pressing close on the heels of her sister 

 on the Cam. 



PROFESSOR MARSH ON THE DINO- 

 CERATA. 



Of late years Professor Marsh has been fol- 

 lowing the plan of selecting a certain group of 

 extinct vertebrates, and thoroughly elucidat- 

 ing its structure in an exhaustive monograph. 

 Where practicable, this plan is by far the most 

 satisfactory method of dealing with the subject ; 

 but it seldom falls to the lot of a paleontologist 

 to obtain his materials in the necessary abun- 

 dance. The volume before us is a magnificent 

 one, surpassing in many respects all other pale- 

 ontological works. Never before has such a 

 remarkably perfect series of mammalian fossils, 

 illustrating a single group, been brought to- 

 gether. Only in the tertiary lake-deposits of 

 western America could such a collection have 

 been formed ; but few can realize what an 

 expenditure of time, labor, skill, and money, 

 even under the most favorable circumstances, is 

 represented by the raw material of this work. 

 Had Professor Marsh done nothing be} T ond col- 

 lecting, he would still be entitled to the lasting- 

 gratitude of all biologists. 



The introduction gives a short but sufficient 

 account of the geology of south-western W} T o- 

 ming, the only region where remains of the 

 Dinocerata have been found. The section il- 

 lustrating this part is open to serious criticism, 

 in that it substitutes for the long-established 

 names of formations given by Ha}' den, King, 

 and Powell, new terms derived from some char- 

 acteristic fossil. Such arbitral changing of 

 accepted names can only result in ' confusion 

 worse confounded.' This section refers the 

 Laramie to the cretaceous, whereas it is almost 

 certainly tertiary. The Puerco is altogether 

 omitted. 



The Dinocerata : a monograph of an extinct order of gigan- 

 tic mammals. By Othniel Charles Marsh. U. S. geologi- 

 cal survey. Monogr. Vol. x. Washington, 1884. 237 p., 56 pi. 



The descriptive part of the book opens with 

 a chapter on the skull, in which the most curi- 

 ous part of these most curious animals is illus- 

 trated with much care. A remarkable and 

 novel feature of .this chapter is the series of 

 sections of the skull which it presents. These 

 sections are made in all directions, — trans- 

 verse, vertical, and horizontal, — and thorough- 

 ly display the internal structure of the skull, the 

 sinuses, cranial cavity, olfactory chambers, as 

 well as the characters of those bones which 

 cannot be seen from the surface. Professor 

 Marsh has here indicated a new method of 

 investigation, which is certain to yield valuable 

 results in the future, as it already has in his 

 hands. Strange to say, the description of the 

 skull ignores almost entirety the basi-occipital, 

 sphenoidal, and periotic regions, as well as the 

 foramina at the base of the cranium. These 

 are most important features, and their omission 

 detracts materially from the value of the chap- 

 ter. The lower jaw receives very thorough 

 description and illustration : its chief peculiar- 

 ities are the backward projecting condyles, 

 and, in the males, the anterior flanges, for the 

 protection of the great upper tusks. Professor 

 Marsh shows that in the females these tusks 

 were very small, and that in consequence the 

 flanges of the mandible are absent or rudimen- 

 tary ; thus correcting the very natural error into 

 which Speir and Osborn had fallen in regard- 

 ing the flange as a generic instead of a sexual 

 character. 



The chapter on the teeth need not detain us 

 except to notice the lower incisors and canines. 

 Osborn and Speir first showed that these teeth 

 differed from those of all other ungulates in 

 having bilobed crowns. In his restoration of 

 ' Tinoceras ' and elsewhere, Professor Marsh 

 represents these teeth as having a very differ 

 ent shape, though the only actual specimen he 

 figures (woodcut 38, p. 37) is an evidently 

 much-worn canine; of 'Dinoceras,' he gives 

 figures of three isolated incisors. We must 

 believe that the restoration of these teeth in 

 ' Tinoceras ' is erroneous. 



Certainly one of the most striking and valu- 

 able chapters in the book is that on the brain. 

 The brain in the Dinocerata " was proportion- 

 ately smaller than in an}' other known mammal, 

 recent or fossil, and even less than in some rep- 

 tiles. It was indeed the most reptilian brain 

 in any known mammal." This is a most re- 

 markable and unexpected fact. This chapter 

 is enriched by an extended and valuable series 

 of cranial casts of mammals from nearly all the 

 tertiary formations. Lartet first pointed out 

 the comparatively small size of the brain in the 



