2. XASENOCETUS. 337 



The cervical vertebrae of Lagenocetus latifrons, as in Hyperoodon, 

 are united into a single mass by the nmon of the bodies of the ver- 

 tebrae, the neural arches, and the lateral processes. 



The united neural arches of the first eervicals are produced, and 

 form a large cone nearly as high as the height of the bodies of the 

 vertebrae, which shelves down before and behind to the upper part of 

 the neural canal, and on the side to the base of the mass, or the end 

 of the large lateral process of the second vertebra, the upper part of 

 the sides being marked with the long deep grooves through which 

 the nerves come out. 



The atlas appears to have no distinct lateral processes, or, what there 

 are, so united to the very large, high, broad, single lateral process of 

 the second vertebra as not to be distinguished from it, except by the 

 existence of the first groove for the exit of the nerves for the upper 

 parts of the body. The lateral process of the second vertebra is 

 massive, conical, and much produced below, on a level with the lower 

 edge of the articular cavity, giving the mass, when viewed in front, 

 an irregular triangular shape. 



The third cervical l>as a broad, short u.pper lateral process, which 

 is only free from the mass at the end ; and this projection is the first 

 appearance of a distinct upper lateral process. The lower process 

 is Hke, but smaller than, the lower process of the second vertebra, 

 and united to the back part of it, making part of the large inferior 

 lateral prominence. 



The fourth and fifth have each an upper lateral process similar to 

 the preceding, but of a much smaller size, being, as weU as that of 

 the sixth vertebra, very small — only small bony plates. These ver- 

 tebrae have no distinct or marked inferior lateral process. 



The seventh cervical, though united to the general mass by the 

 body of the vertebra, is yet well defined from the rest of the mass, 

 and retains the usual form of the separate vertebrae of the animals. 

 The neural arch is of the same form as those of the other cervical 

 vertebrae, but much smaller, and not so high ; it is separate from the 

 large conical mass which they constitute, forming a pointed, rather 

 projecting arch at the hinder side of the mass. The upper lateral 

 process is similar in form to the upper lateral process of the two 

 or three cervical vertebrae that precede it; but it is much larger 

 than these, and bent forwards at the end to unite with the ends 

 of them. 



The lower lateral process is very thick and large, forming- a' large, 

 short tuberosity on the under part of the mass, but quite separate 

 from it. The articulating surface of this vertebra is oblong, erect, 

 rather higher than wide, with a deep suture from the centre to the 

 middle of the upper margin. 



The front of the canal of the sjnnal marrow is triangular, about 

 as high as wide, with the angles rounded, the upper side being 

 transverse, and the lower ones converging. The hinder part of 

 the canal, on the contrary, is trigonal with the upper sides con- 

 verging, the lower side being rather wider than the height of the 



