228 Bones of the Zeuglodon. [April, 



the spinous process, 7 inches. Diameter of the spinal canal, 2 

 inches; transverse diameter of the spinal canal, 3j inches. This 

 process is rather attenuated, slender and high in proportion to the 

 thickness of the vertebrae. It is evident from the number and 

 size of those vertebras that the Zeuglodon was furnished with a 

 long slender neck, and in this respect exhibits one of the ex- 

 tremes among the cetacea. 



Tooth. — Fig;, 3. This is the natural size of the tooth, and is 

 perfect in all respects. The drawing conveys a perfect idea of 

 its shape and character. The serratures are sharp, and seem 

 never to have been used. Indeed, all the teeth of this animal 

 exhibit a perfect condition, which belongs only to teeth whose 

 office is merely that of seizing and holding its prey; or else, the 

 teeth of a young animal. The crowns are never worn by masti- 

 cation. 



Base of the Loioer Jaw. — Plate I., fig. 1.* This is perhaps one 

 of the most interesting bones in the collection. Its height at the 

 coronoid process is 10 inches, and the whole length of the piece 

 17 inches, a, large sm-face is a mere cast, as the part at a has 

 the form of the hollow portion. 6, coronoid process, c, condyle, 

 which in comparison with the size of the jaw is quite small. 

 Outer surface convex; inner, concave. The four back teeth in the 

 jaw remain, of which the anterior one is not represented in the 

 engraving. In consequence of the exfoliation of the convex part 

 of this bone, the jaw tapers more rapidly than natural. 



Small Caudal Vertebra. — Fig. 2. The body has the usual form 

 of a vertebra, but there are no transverse or spinous processes, 

 not even rudiments of them. The superior face supports two 

 processes, one on each side, which stand upward, backward and 

 outward, having a wide space between them. Their length must 

 have been one and a half to two inches. About three-fourths of 

 an inch remains. Transverse diameter, 3.^-; perpendicular diame- 

 ter, 2|; length measured over the superior margin 2\, at the infe- 

 rior 2 inches. A bony rough ridge runs longitudinally between 



• The engraver not being an anatomist has turned the upper edge down. 



