BLAKE — EVIDENCES OE HOUSES IN THE NEW WOULD. 



27 



species of Ilipparion and Fquus should exhibit the more generalized 

 type of perissodactyle dentition. 



Equus piscenensis, Gervais, Zool. and Paleontol. Frangaises, 

 p. 07, pi. 21, jigs. 9, 10. (Upper portion of the cannon bone of the 

 forefoot ; first phalanx.) This species, smaller than the horse, has 

 been founded by M. Gervais on the above bones of the extremities. 

 The teeth are wholly unknown. 



Geog. Distrih. Bight bank of the liiege, near Pczenas (Ilerault). 



— Geol. Age. Pliocene. 



Equus pal iE onus, Equus sivalensis, Equus Namadicus. — These 

 three species are figured in Falconer and Gautleifs ' Fauna Antiqua 

 Sivalensis? but no description is there given. The figured specimens 

 are in the British Museum. 



Equus curtidens, Owen in ' Fossil Mammalia oftlie Voyage of the 

 Beagle? p. 108, pi. %%figs. 13, 14. 



Characters. — Molar teeth left side upper jaw, slightly smaller and more curved than 

 E. caballus. A superior molar of the right side was derived from Bahia Blanca, but its 

 friable condition precluded its representation in Professor Owen's work. 



Geog. Distrib. Punta Alta (Bahia Blanca), Santa Ee in Entre liios. 



— Geol. Age. Pliocene. 



Equus neogjeus, Lund. — Syn. Equus macrognathus {Weddell, p. 

 204). E. principalis, Lund, Ann. des Sci. jtfat. xii. p. 309. Equus 

 Devillei, Gerv. 



Mr. Lund, the founder of the species, characterizes it by the greater 

 breadth and flatness of the metatarse than any existing horse. The 

 name macrognathus is founded on the greater length of the diastema 

 in the Tarija specimens. The two lobes of the lower molars are more 

 distinctly separated than in the F. caballus, although there is no inter- 

 rupt ion in the ribbon of enamel. 



Castlenau calls attention to their more generalized type in the fol- 

 lowing words : — " Before the crowns are worn, the thickness of the 

 cement gives them a rather peculiar appearance, which makes them, 

 up to a certain point, resemble those of Rhinoceros, because the arched 

 form of each of their lobes is then more apparent, and because the 

 ends of each curve are prominent in a tubercular form." 



Fquus Devillii is not characterized by Lund, but Gervais figures a 

 fragment of lower jaw, and an astragalus, the proportions of which 

 are different from those of F. neogaus. The differences in the molar 

 teeth are however very slight. 



Geog. Distrib. Tarija (Bolivia, Brazil). — Geol. Age. Pliocene. 



Equus Cuilensis. — Syn. Equus Americanus (Gay,i. 14G). (Third 

 lower molar, left side.) 



Characters. — Molars as large as those of Equus caballus , and perhaps a little thicker: 

 having the same general arrangement of enamel, dentine, and cement as it, hut differing iu 

 some minor modifications. Thus, the "conformation of the curves {las rt'dondeces colo- 

 caclas) attached to the inner border of the crown is somewhat more broad, and the 

 space in the little isthmus which joins the first and second of these inner curves to the 

 two oval ones outside, is also more broad and with plications less crcuulatcd {frisailo). 

 (Gay, loc. cit.) 



