1868.] DAWKINS RHINOCEROS ETRTJSCUS. 209 



height of the entrance of the anterior valley, a, above the cingulum, 

 is also a point of difference. In this case it is worn away. 

 There is but little difference observable between true molars 1 and 2. 

 In both the guard is very strongly marked on the anterior aspect, 

 and is represented, more or less, by a line of small obtusely pointed 

 cusps passing across the anterior collis, d, and the posterior, e. In 

 the first true molar it is not observable on the inner aspect of d, but 

 it blocks up the entrance into the anterior valley, a ; while in the 

 second it is visible on the former and absent from the valley-entrance. 

 In both it is present on the inner base of e. The entrance of the 

 anterior valley, a, is wide, the posterior combing-plate, h, is very 

 large. The third collis, e, is notched and cuspless, as in the Mega- 

 rhine and Leptorhine teeth. The two anterior costae, and especially 

 the second, h 2, are strongly marked ; and the posterior area, n, is 

 excavated, and inclines very much inwards as it approaches the 

 grinding- surface of the crown ; at the point, however, where it joins 

 the cingulum it is tumid. A ridge sweeps round the bottom of the 

 laminae, and connects costa 1 with costa 4. These last two points 

 are highly characteristic. The last true molar (PL YIII. fig. 4), which 

 is about half worn, is remarkable for the great width of its valley - 

 entrance, and for the great development of the posterior combing- 

 plate, 7t, which passes across the valley and is fused to the anterior 

 coUis, d, and thus insulates the head, c, of the anterior valley, a. 

 The guard, o, is very stout on the anterior aspect of d, and is repre- 

 sented by a line of cusps at the inner base of the latter. The pos- 

 terior valley, h, is a faint depression behind the median collis, e, 

 circumscribed by a cuspless ridge of enamel homologous with the 

 third collis, /, in the upper molar series. 



In the Rev. S. "W. King's collection there are several isolated teeth 

 belonging to the Etruscan species, and all obtained from the Forest- 

 bed on the east coast. A right upper true molar 3* reproduces all 

 the characters of that which has been just described. Two premolars 

 also correspond exactly with the third premolar of the Pakefield 

 jaw, while the third, or the first premolar (Pm. 2) of the right side, 

 is remarkable for the development of an accessory combing-plate. 

 Its posterior collis is notched and cuspless. The entrance of the 

 anterior valley and the cingulum are situated respectively 0*82 and 

 0*48 inch from the base of the crown. Among the teeth of Hhi- 

 noceros forwarded to me by the Rev. John Gunn, is a small right 



♦ E. Etruscus, Falc. ; syn. B. leptorhinus, Cuv., pro parte, i?. tichorhinus auc- 

 torum. Last true molar, upper jaw, right side, half-worn, and presenting the 

 distinctive characters of the species. The imperfect pit (^uits) at the base of the 

 posterior inner angle is developed exactly as in the specimens from the Val 

 d'Arno, and as in a specimen from Malaga with which it was confronted. The 

 enamel still is thin, and the outer surface is marked by very fine, parallel, 

 closely appressed grooves. The tooth differs from the ordinary character chiefly 

 in having the plate which is thrown off from the posterior barrel continued 

 aci'oss the valley so as to form a bridge between the anterior and posterior 

 barrels, isolating a portion of the transverse fissure into a round hole. Tliis 

 character is rare among the Rhinocerose.s. (Dictated to the Rev. S. W. King bv 

 Dr. Falconer, 13th December, 1861.) 



