390 DA VISON. [Vol. XI. 



the fascial body investment. That side of the base proximal 

 to the axis is continued forward as the distal side of a cone in 

 the adjacent row. Therefore it is seen that a transverse line 

 through the apex of a cone in one row will pass through the 

 base of a cone in the adjacent row. 



In the middle row the deep sides of the bases are attached 

 to the post-zygapophyses and their spines. The distal and 

 proximal sides of the bases are continued as the lateral bound- 

 aries of cones in the adjacent rows. The superficial sides of 

 the bases have the same insertions as those in the row previ- 

 ously described. The cones in the row adjacent to the axis 

 are somewhat flattened laterally by their close apposition to 

 the neural spines. The deep side of the base of each cone is 

 securely inserted on the postero-lateral division of the neural 

 spine. The distal side of each base takes the same course as 

 the corresponding side in the adjacent row. The proximal 

 sides are fastened to the neural spine and also to the fascia 

 arising from the neural spines to serve as the body investment. 

 The superficial sides of the bases and also one-half of the 

 superficial lateral boundaries of the cones are blended with the 

 external fascial envelope. The apices of the cones in this row 

 give off ribbon-like tendons which extend to the interior of the 

 following apices. Such is the general arrangement of the 

 cones in the superior dorsal mass. 



The size of these cones varies. Those of the distal row are 

 all of the same size, and are somewhat larger than those of 

 the other two rows, the length being fully three centimetres, 

 and the diameter of a base about one and a half centimetres. 

 The length of a cone in the proximal row is scarcely two cen- 

 timetres, and its base is about one-half a centimetre. The 

 preceding measurements were made on an animal almost one 

 metre long. 



Since the arrangement of these cones is so regular, it is 

 easy to estimate their number, which I have calculated to be 

 three hundred and seventy-two in the superior dorsal mass. 



A view of the inferior mass from within the body cavity 

 reveals no evidence of a conical arrangement, but instead are 

 seen, very prominently marked, the transverse septa at regular 



