620 



SCIENCE 



[N. S. Vol. XXIX. No. 746 



mental. Hence this book ■will be available, 

 particularly as a reference book, in many 

 laboratories. The discussion of elementary 

 elastic theory is excellent and not beyond the 

 average undergraduate. More time is evi- 

 dently given to elasticity by Mr. Searle's stu- 

 dents than is usually possible in American 

 colleges and universities for this part of phys- 

 ics. The only criticism that might be made 

 is that several of the experiments given are 

 very complicated for a practical physics 

 course, but these are added experiments so that 

 none of the standard experiments have been 

 crowded out. A. P. Carman 



SPECIAL ARTICLES 



A NEW GENUS OF CARNIVORES FROM THE MIOCENE 



OF WESTERN NEBRASKA 



While engaged in restudying the material 

 described' as Amphicyon superbus by the 

 writer in the Annals of the Carnegie Museum, 

 Vol. IV., p. 51, it has become apparent that 

 the species, though allied to the European 

 forms, should be regarded as generically 

 distinct from them, and that it is more nearly 

 related to Daphcenus from the Oligocene of 

 North America. The type specimen con- 

 sists of a practically complete skeleton, which 

 has been freed from the matrix and is ready 

 for mounting. It is now being restudied and 

 described in detail by the present writer. 



For this new genus from the Miocene for- 

 mation of western Nebraska I propose the 

 name Daphcenodon. The dentition and 

 cranium show close similarity to Daphcenus 

 from the Oligocene, and the latter genus ap- 

 parently represents the ancestral stock from 

 which the proposed genus Daphcenodon is 

 descended. 



Daphcenodon, gen. nov. 



(Type Daphoinodon superbus (Peterson), 

 Specimen No. 1589, Car. Mus. Catalog Vert. 

 Poss.) 



Principal Generic Characters: Cranium 

 comparatively short, hroad, and low; muzzle 

 large, sagittal crest prominent; hrain-case 

 small; incisors heavy and short; canines com- 

 paratively small and oval in cross-section; P* 



with antero-internal cusp of moderately large 

 size; W and W large and hroad; W present, 

 though small, practically one-rooted and 

 aligned with the internal border of W and W. 



Upon very careful comparison of the type 

 specimen of Daphcenodon superbus with casts 

 of Amphicyon giganteus {A, major Blain- 

 ville) and also with illustrations of the best 

 known European forms^ it is evident that 

 there are characters of considerable impor- 

 tance, which may be regarded' as of generic 

 value. The more important differences may 

 be stated as follows: 



The skull of Amphicyon giganteus is repre- 

 sented only by the left maxillary, but it indi- 

 cates a cranium having considerably greater 

 elevation from the alveolar border of the 

 maxillary to the nasals than is the case in 

 Daphcenodon superbus. It isi also seen that 

 the alveolar border is more strongly developed 

 posteriorly in the European genus, M° being 

 succeeded by a considerable process of the 

 maxillary, while in the American genus the 

 border back of M° is extremely thin. 



In the European form, A. giganteus, the 

 canine is of very large size, sharply pointed, 

 has a decided cutting edge posteriorly and a 

 prominent rib on the antero-internal angle, 

 which causes the crossi-section of the tooth to 

 be very elliptical, as in certain cats of the 

 Oligocene, while the corresponding tooth in 

 Daphcenodon superbus is proportionally much 

 smaller, the edges not so sharp in front and 

 behind, and the tooth consequently having a 

 more oval cross-section. The superior pre- 

 molars in the European genus are proportion- 

 ally smaller, P* has a distinctly smaller an- 

 tero-internal tubercle and the long axis of the 

 crown is more nearly antero-posterior, the 

 tooth being placed less obliquely in the jaw 

 than is the case in Daphcenodon superbus. 

 The superior molars of the latter genus differ 

 in some important particulars, viz. : M* is of 

 relatively greater transverse diameter and the 

 posterior intermediate tubercles, especially 

 the one on M^ which closes the posterior 

 opening of the median pit in Amphicyon 

 giganteus, are absent. M° of the latter genus 



' Blainville, Vol. II., PI. XIV. ; Filhol, Ann. Soo. 

 Geol., X., pp. 77-79, PI. 10-16, 1879. 



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