August 13, 1909] 



SCIENCE 



221 



Be this as it may, horses with teeth of the 

 E. stenonis type existed in the south of Scot- 

 land during the first and second centuries, and 

 horses with short-pillared cheek teeth are still 

 in existence. In some of the skulls from the 

 Roman fort at Newstead, the anterior pillar of 

 the third and fourth premolars only measures 

 9 mm. — is only about half the length of the 

 pillar in E. namadicus and other " fossil " 

 Pleistocene species. Further, in one of the 

 first century Newstead skulls, the first pre- 

 molar is as large as in E. stenonis, and the 

 face (as broad and long as in E. sivalensis) 

 forms an angle of 18° 6' with the cranium. 



Further enquiries may show that the short- 

 pillared species (with metacarpals as long but 

 somewhat thicker than in E. sivalensis) widely 

 distributed over Europe and north Africa, in 

 Pliocene times played an important part in 

 the making of Shires and other heavy modern 

 breeds. 



The only other possible ancestor dealt with 

 in this contribution is the one to which I have 

 given the name Equus gracilis. 



Owen arrived at the conclusion that Pleisto- 

 cene horses " had a larger head than the do- 

 mesticated races " and that even in small 

 varieties the teeth were nearly as large as in 

 a modern cart horse. 



Having come to these conclusions it is not 

 surprising that when it fell to his lot to de- 

 scribe small equine molars from the drift 

 overlying the London Clay and from a cavern- 

 ous fissure at Oroston, near Plymouth, he 

 decided that they could not belong to a true 

 horse and (on the assumption that they be- 

 longed to an extinct ass or zebra) formed for 

 them the species Asinus fossilis. In addition 

 to the small second and third molars described 

 and figured by Owen, there is in the British 

 Museum a small first molar from Oreston. 

 The anterior pillars of the second and third 

 Oreston molars are more than half the length 

 of the crown, as in horses of " forest " type, 

 but the pillar of the first molar, m. 1, from 

 Oreston is only about one third the length of 

 the crown, as in Pliohippus and E. stenonis. 

 Except in size, the small teeth from Oreston 

 and other Pleistocene deposits bear little re- 



semblance to the molars of asses or zebras, but 

 they are practically identical in enamel fold- 

 ings, as well as in size, with the molars of a 

 small (12.2 hands) slender-limbed horse in the 

 possession of the Auxiliaries who garrisoned 

 the Roman fort at Newstead in the south of 

 Scotland about the end of the first century. 



In addition to small equine teeth the Devon- 

 shire Pleistocene deposits have yielded a small 

 slender metacarpal. This metacarpal (from 

 Kent's Cave near Torquay) is 220 mm. long 

 and 30.25 mm. wide — the length is hence 7.27 

 times the width, as in fine-boned Arabs. 



As might have been anticipated from a 

 study of the teeth, the Kent's Cave metacarpal 

 belongs to a very much finer-limbed race, than 

 the small horse of the " elephant " bed at 

 Brighton. On the other hand, the Kent's Cave 

 metacarpal vei-y closely agrees with the meta- 

 carpals of the small Newstead horse. This 

 small first century horse in teeth and limbs 

 agrees with Exmoor, Hebridean and other 

 ponies of the " Celtic " type, i. e., with ponies 

 characterized by a small fine head, large eyes, 

 slender limbs, five lumbar vertebrae and by the 

 absence of the hind chestnuts and all four 

 ergots. 



It hence follows that the small equine of the 

 English Pleistocene (Owen's Asinus fossilis) 

 instead of being an ass or a zebra, is a true 

 horse which in the metacarpals as in the 

 " pillars " of the premolars and first molar, 

 differs but little from Pliohippus of the late 

 Miocene and early Pliocene American de- 

 posits. 



Remains of a small horse with teeth and 

 limbs like Equus gracilis (Asinus fossilis 

 Owen) have been found in the Pliocene de- 

 posits of Italy and France, and in the Pleisto- 

 cene deposits of France and north Africa. 

 The Italian and Auvergne slender-limbed 

 horse has generally been regarded as a small 

 variety of E. stenonis. By Pomel and other 

 paleontologists this French variety was known 

 as E. ligeris, while the north African variety, 

 named Equus asinus atlanticus by Thomas, 

 was regarded by M. Boule as closely allied to, 

 if not the ancestor of zebras of the Burchell 

 type. 



