212 



PROCEEDINGS OP THE GEOLOGICAL SOCIETY. 



Jan. 8, 



The left ramus (PL YII. fig. 3) shows the typical molar dentition. 

 Many other lower jaws of the Etruscan sjiecies have also been obtained 

 from the Forest-bed ; one left ramus in the possession of Mr. Eitch, 

 of ]N'orwich, was considered by Professor Owen* to belong to his Lep- 

 torhine species. Its correspondence, however, with other jaws which 

 are indisputably Etruscan, place its determination beyond all doubt, 

 although the only teeth it presents are the last milk-molar and the 

 germ of the true molar f. In the Norwich Museum there is a right 

 lower ramus, which belonged to an old adult, and a last true molar, 

 both of which were obtained by Miss Gurney fi'om the Forest-bed. 

 In the Geological Museum at Cambridge there are also two rami 

 that contain four out of the six molars, and belonged to an animal 

 in the prime of life. They were found in the same locality as the 

 preceding, by Miss Gurney. A left lower ramus containing the true 

 molar series was forwarded to me by the Eey. John Gunn, which 

 had been named by Dr. Falconer Bhmoceros Jeptorhinus of Cuvier. 

 Its characters, however, read by the light of discoveries since his 

 death, show that it really belongs to JRJdnoceros Etruscus. There 

 are also a few specimens in Britain of the lower molars oi Ehinoceros 

 Etruscus from foreign localities, consisting of a lower jaw fi^om the 

 Yal d'Arno in Mr. Pentland's collection at Oxford, and some isolated 

 teeth from Perolles in the British Museum, j^one, without excep- 

 tion, that have passed through my hands, present any deviation 

 from the characters which have been ascribed above to the lower 

 molars of BJihioceros Etruscus. 



5. ComjjcLrative Measurements. — The measurements taken at the 

 base of the crown in inches and tenths are uniform with those of 

 the preceding essays on the Tichorhine, Megarhine, and Leptorhine 

 dentition. They are — 



1. Antero-posterior, taken along the outside of the crown. 



2. Antero-ti'ansverse, taken across the anterior lobe of the tooth. 



3. Postero-transverse, taken across the posterior lobe of the tooth. 

 A comparison of the measurements of the Etruscan teeth with 



those of the Pliocene and Miocene species will show the difference 

 of size existing between them. 



Table oe MJEAsrEEMEXTs. 

 Vp^er Molar Series. 



Species. i Locahty. | Tooth. 



1. 



2. 1 3. 



1 



( 



i ( 



Pm. 2il-24 



1-4 



1-62 





i 



i 



Pm. 3 



1-48 120 



2-02 





j 



Pm. 4 



1-5 



2-16 J2-15 1 







M. 1 



1-75 



2-36 2-2 



Rhinoceros Etruscus 



Pakefield, Lowestoft • 



M. 2 

 1 M. 3 



1-78 



2-42 2-16 







M. 2 



1-8 



2-4.5 2-2 





" 



M. 1 



1-8 



2-38 212 







Pm. 3 



1-45 



205 205 



< 



I 



Pm. 2 



1-22 



1-49 1-66 



* Brit. Foss. Mammals, p. 381. 



t See Falconer's note, § 2. 



