148 



SCIENCE 



[N. S. Vol. XXXI. No. 787 



A careful revision of the family, genera and 

 species follows in which are descrihed as valid 

 the genera Enielodon with two species ; Archw- 

 otherium with four species and one subspecies 

 ■ — including those usually grouped under the 

 genus Elotherium; the subgenus Pelonax in- 

 cluding three species; Dceodon, two species; 

 Dinohyus, one species, and Ammodon, one 

 species. The forms known as Elotherium im- 

 perator and Elotherium superhum can not be 

 generically determined. 



A history of the discovery and working of 

 ■the famous Agate Spring Quarry follows to- 

 gether with geologic notes and a diagram of 

 the Miocene section. 



In discussing the cause of the deposit at 

 Agate Spring which has rendered up so abun- 

 dant and wonderfully preserved a fauna, Mr. 

 Peterson imagines the location to have been 

 the favorite crossing place of a stream which 

 at times contained engulfing quicksands. The 

 remains are those of animals which attempted 

 to cross at the unfavorable intervals. 



A detailed description of that marvelous 

 Suilline, Dinohyus hollandi, is next given — a 

 brute of rhinocerine bulk. Two restorations 

 are given of the skeleton, one of which is an 

 actual photograph of the mounted specimen 

 followed by that of a model showing the pos- 

 sible appearance of the animal in the flesh. 



In conclusion Peterson tells us that the 

 Entelodontidas constituted a collateral branch 

 of the Suidse which diverged in early Eocene 

 time. They are nearest the pig and hippo- 

 potamus among recent forms. 



In geographical distribution they are found 

 especially in Europe and North America, none 

 as yet having been reported from Asia. They 

 were comparatively abundant on the flanks of 

 the Eocky Mountains and existed also in Cali- 

 fornia and New Jersey. From the Lower 

 Oligocene upward and before the close of the 

 Miocene they occupied certain areas from the 

 Pacific to the Atlantic coasts of North 

 America. 



Mr. Peterson's work shows painstaking care 

 and thought and advances our knowledge of 

 this interesting group very materially. It is 



especially valuable in the clearing up of 

 synonymies and in defining the various valid 

 types. KiCHAED S. Lull 



Yale Univebsity 



The Cranial Anatomy of the Mail-cheehed 

 Fishes. Edward Phelps Allis, Jr., in 

 Zoologica (herausg. von Professor Dr. Carl 

 Chun), H. 5Y, B. 22. Stuttgart. E. 

 Schweizerbartsche Verlagsb. 1909. Quarto, 

 219 pages, 8 plates. 



This is another example of the painstaking 

 descriptive work for which zoology is so greatly 

 indebted to Mr. Allis. The work is illustrated 

 by splendid lithographic plates after drawings 

 by the artist Nomura from special prepara- 

 tions. The greater part of the paper is de- 

 voted to the descriptive anatomy of the skele- 

 ton of the head, and its chief value lies in the 

 attention to detail in the text and the accuracy 

 with which the figures are executed. The 

 morphology of the myodome and the criteria 

 of segmental relations in the cranial nerves 

 are discussed at some length. The myodome 

 is believed to be the homologue of the cavern- 

 ous and intercavernous sinuses of the human 

 skull. 



With regard to the segmental relations of 

 cranial nerves, Allis states that " there is a 

 marked tendency to consider the central origin 

 of a given cranial nerve of much more impor- 

 tance for the determination of its segmental 

 position than the course of the nerve and its 

 general relations to the skeletal elements." 

 This he attributes to the acceptance of the 

 neurone theory, according to which nerve fibers 

 follow always the path of least resistance to 

 their destination. According to this concep- 

 tion the points of origin of nerve components 

 in the central nervous system give the only 

 positive criteria as to their segmental position, 

 and their peripheral course is explained by 

 accident, individual experience or elective 

 selection. The author thinks this view unfor- 

 tunate and not well founded. 



The reviewer has never observed the tend- 

 ency of which Mr. Allis speaks. On the con- 

 trary, the segmental position of a nerve is 

 determined primarily on the basis of its periph- 



