No. 2.] AMPHIUMA MEANS. 39 1 



intervals, corresponding to the lengtlis of the vertebrae. It 

 will be noticed, however, that the septa appear to cease very 

 abruptly at a distance of two-thirds of a centimetre from the 

 axis. A careful dissection of a well stained specimen along 

 this line brought to view the same conical arrangement ob- 

 served in the superior mass. The cones in the distal and 

 middle rows are quite perfectly developed, but those of the 

 proximal row are very imperfectly formed, being too closely 

 apposed to the spinal axis. The direction of the apices in these 

 rows is exactly opposite to those in the superior mass ; that is, 

 the proximal row of cones has its bases pointing anteriorly, 

 whereas in the corresponding row of the superior mass the 

 apices pointed posteriorly. The cones are much smaller, being 

 scarcely half as large as the overlying ones. The superficial 

 sides of the bases, as well as a large part of the superficial 

 lateral area, are inseparably united to the dense fascia lining 

 the body cavity. The outer sides of the bases in the distal 

 row are reflected to form the transverse septa, while the deeper 

 sides of the bases are firmly attached to the lower side of the 

 outer half of the transverse processes. The inner sides of 

 these bases are continued to form the lateral boundary of a 

 cone in the adjacent row. The attachments of the middle row 

 are so similar to those of the same row in the superior mass 

 that I will not give them. The apices of these two rows are 

 connected with the interior part of the apices of the cones 

 following by a ribbon-like tendon. 



In the row adjacent to the spinal axis the deep sides of the 

 bases adhere to the hypapophyses of one vertebra, and the 

 apices are inserted on the hypapophyses of the vertebra follow- 

 ing, so that each hypapophysis serves for the attachment of an 

 apex and the deep side of a base. From this brief description 

 it can be readily seen that the general plan of the cones is the 

 same in both dorsal masses. 



The conical arrangement of the muscles prevails not only in 

 the dorsal portion of the tail of Amphiuma, but also in the 

 ventral portion. The disposition and attachments of the cones 

 here are so very similar to those of the trunk region that it 

 would be unprofitable to describe them. The number of cones 



