54 FAUNA ANTIQUA SIVALENSIS. 



British Museum. It is of an age intermediate between the specimens 

 figured in Plate XXXV. 3, and Plate XL. 18. It is very valuable, 

 and is believed to be at present unique in Europe. 



Length of fragment of jaw, 15" in. Breadth, 4*3 in. Height, 4 - l in. Length of 

 first molar, 4 , in. Breadth, 2'6 in. Length of second molar, 5 - 5 in. Breadth, 

 27 in. 



Fig. 16. — Mastodon Oliioticus. Fragment of upper jaw, with three 

 ridges and fangs of last tipper molar, also empty cavity in jaw for fang 

 of fourth ridge.— B.M. 



Length, 5'1 in. Width, -4' in. Height of crown and fang, 7' in. 



Fig. 16 a. — M. Oliioticus. Last true molar, upper jaw, with four 

 main ridges and a heel ; the first ridge only very slightly touched by 

 wear. In Mastodon Oliioticus the upper teeth are distinctly cleft 

 lengthwise into two divisions, each division being indistinctly composed 

 of a pair of confluent points. The plane of the tooth is oblique, sloping 

 from the outside, which is higher, to the inside, which is lower, and 

 this relation continues during the wear, the inside being the most worn. 

 The inner division, both anteriorly and posteriorly, throws off the 

 decurrent talon crests, but in the first two milk teeth the inner division 

 is smaller than the outer. Precisely the reverse is seen in lower jaw, 

 the inner ridge being the highest and remaining so during detrition, 

 while the outer is the lowest but least complex. — B.M. 

 Length, 7"3 in. Width, 4- in. 



Plate XLI. 



Tusks of Proboscidea. 1 Fragments and sections. 



Figs. 1 and 1 a. — Twisted fragment. — B.M. 



Length measured along great curvature, 40 1 in. Direct length or chord of cur- 

 vature, 28 - in. Circumference at proximal end, 127 in. Circumference at distal 

 end, 13-2 in. 



Fig. 2.— B.M. 



Length, 56" in. Circumference at proximal end, 13 - 5in. 



Figs. 3 and 3 a.— B.M. 

 Length of fragment, 12 - 2in. Circumference, 12 - 2in. Greatest diameter, 37 in. 



Figs. 4, 4 a, and 4 J.— B.M. 



Length of fragment, 127 in. Greatest diameter, 7'7in. Smallest diameter, 

 5" in. 



Fig. 5.— B.M. 



Greatest diameter, 9 - 8 in. Smallest diameter, 7'2 in. 



Figs. 6 and 6 a. — Fragment of tusk in socket. 



Length of socket, 135 in. Circumference of tusk, 6 - 2in. Breadth of incisive 

 alveolar margin, 6 - 2 in. 



Figs. 7 and 7 a.— B.M. 



Length, 68 - in. Circumference at proximal end, 11" in. 



Figs. 8 and 8 a,— B.M. 



Length of fragment, 33 - in. Circumference at smaller end, 165 in. 



1 There is no evidence of any attempt ! the plate (with the exception of figs. 6 

 made hy Dr. Falconer to determine the ! and 25) are collected in one place in the 

 species to which any of these specimens British Museum, 

 belonged. AH the specimens figured in | 



