672 SCIENCE PROGRESS 



the Pleistocene. In addition to remains of the horse and ass, 

 there are fragments of jaws at Grimaldi referable to the extinct 

 Equus stenonis of the Upper Pliocene and Lower Pleistocene, 

 In the opinion of the author, E. stenonis and the allied Indian 

 E. sivalensis represent a stage intermediate between the modern 

 Equits cabalhis and the extinct Protohippiis, which (and not 

 the thVee-toed Hipparioti) was the proximate ancestor of the 

 existing members of the family. Protohippits, said to be known 

 only from America, although it may have existed in Asia/ 

 was three-toed, but had the lateral digits functionless. In the 

 aforesaid extinct species of Equus these bones became reduced 

 to mere splints, much as in the modern members of the family. 



The hyracoids of the Fayum are discussed by Dr. Schlosser 

 in the paper already quoted, which contains descriptions of new 

 genera and species. 



One of the most important pieces of palaeontological work 

 in the year is Dr. W. B. Scott's account of the Litopterna — a 

 group typified by the well-known Macrauchenia — of the Santa 

 Cruz beds, published as vol. vii. pt. i of the palaeontological 

 series of the Reports of the Princeton University Expeditions to 

 Patagonia. In regard to the affinities of the group, Dr. Scott, 

 as he himself states, arrives at a conclusion very similar to one 

 expressed by myself several years previously. The Litopterna, 

 in the opinion of Dr. Scott, are more nearly related to the 

 Toxodontia than to the Perissodactyla, the striking resemblances 

 to the latter being largely due to parallelism of development, 

 although in part to the retention of primitive features common 

 to all early ungulates, if not indeed to mammals generally. 

 This conclusion as to the absence of near affinity between 

 Litopterna and Perissodactyla receives strong support from the 

 fact that the earlier members of the two groups show no signs 

 of closer approximation than is exhibited by their later and 

 more specialised representatives. In fact, the exact converse of 

 this is true, since the closest resemblance between the two 

 groups is displayed by the Proterotheriidce on the one hand 

 and the Equidce on the other. It may accordingly be assumed 

 that the Litopterna and Toxodontia form two sections of an 

 assemblage of ungulates peculiar to South America which 

 originated in that continent from some at present unknown 

 ancestral type or types. " The primitive features of the Lito- 

 ' It was recorded from Russia by Madame Pavlow in 1903. 



