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383. The fifth and last molar, left side, upper jaw. Purchased. 



384. A portion of the first molar tooth, right side, upper jaw. Purchased. 



385. The fourth molar tooth, right side, upper jaw : the transverse striae on the 



outer surface of the cement are well displayed in this specimen. 



Purchased. 



386. The fifth and last molar tooth, right side, upper jaw. Purchased. 



38/. The third molar, left side, lower jaw. The grinding surface is obliquely 

 fractured. Purchased. 



388. The fourth and last molar, left side, lower jaw. This is the largest and 



most complicated tooth of the series, resembling two simple molars joined 

 together lengthwise. Purchased. 



389. A portion of the third molar, right side, lower jaw ; including the grinding 



surface. Purchased. 



390. A portion of the right ramus of the lower jaw of the Mylodun robustus, 



including the two posterior molar teeth and part of the socket of the 

 second molar, with a portion of the coronoid and angular processes and 

 the commencement or entry of the great dental canal. 



Purchased. 



391. The symphysis of the lower jaw of the Mylodon robustus. This part 



forms the most remarkable feature of the lower jaw and resembles the 

 blade of a spade ; it is inclined from below upwards and forwards at an 

 angle of 130° with the basal line, as a broad, nearly square plate of bone, 

 diminishing in thickness to its upper margin, which is nearly straight. 

 The trenchant anterior edge is a little roughened for the attachment 

 doubtless of a callous gum ; it offers no trace of incisive sockets ; it 

 forms a right angle with the lateral margins of the symphysis, which are 

 slightly concave ; each angle is rounded off. The inner surface of the 

 symphysis is smooth and concave at its anterior half, convex vertically 

 at its lower half; but here, also, smooth, and without any ridge or 

 process indicating attachments of genio-hyoid or genio-glossal muscles. 



k 2 



