510 SCIENCE PROGRESS 



of the lower jaw. In the opinion of Mr. Douglass, the owner 

 of this skull was furnished with a proboscis of considerable 

 length. The development of horns is probably a sign that 

 the genus belonged to a decadent, or over-specialised, member 

 of the group. Another member of the same genus is described 

 by the author in the Bulletin of the American Museum, vol. xxiii. 

 art. 32. Skulls of a number of other forms of these curious 

 " ruminating hogs " are described in the same two papers, but 

 since they belong to well-known genera, further mention is 

 needless. 



The work on the swine group is suggestive of somewhat 

 unnecessary genus-making. In a paper published in the 

 Memoirs of the Carnegie Museum (vol. ii., No. 8) Mr. O. A. 

 Peterson described a peccary from the Miocene of Nebraska 

 under the name of Thinohyus siouxensis. According, however, 

 to Dr. Matthew, Thinohyus is inseparable from the White River 

 genus Perchcerus ; but instead of referring Peterson's species to 

 that genus, he proposes the new generic name Desmathyus for 

 a more or less closely allied animal, and regards " Thinohyus " 

 siouxensis as a primitive aberrant form transitional from Per- 

 chcerus. Surely in such a case it would be better to include 

 all three forms in one genus. In these Miocene and Oligocene 

 peccaries there were three pairs of upper incisor teeth, instead 

 of the two of the modern Dicotyles; but in some of the Miocene 

 species the outer pair is much reduced in size. These later 

 Miocene forms also agree with modern peccaries in having 

 the tympanic bulla of the skull filled with cancellous bony 

 tissue, whereas in the typical Perchcerus it is empty. 



The evolution of the horse and the mutual relationships of 

 the different domesticated breeds are subjects which continue 

 to attract the attention of investigators on both sides of the 

 Atlantic. Dr. R. S. Lull has drawn up a useful summary of 

 the main facts connected with the evolution of the horse family, 

 which first appeared in the March number of The American 

 Journal of Science, but has been reprinted in pamphlet form 

 as a guide-book to the collection in the Peabody Museum at 

 Yale University. Prof. J. C. Ewart, on the other hand, has 

 devoted his attention to a large series of horse-skulls discovered 

 in the Roman fort at Newstead, near Melrose, and published 

 the results of his investigation in the Transactions of the Royal 

 Society of Edinburgh, with a summary in an article in the 



