174 OEiaiNAL ABTICLES. 



long cylindrical processes, striking nearly vertically downwards. 

 The first is in contact, at its extremity, with the second. 



There are no traces of any transverse processes, nor are there 

 any ribs. Along the middle lateral line a strong fibrous septum 

 runs, attached, on the one hand, to the vertebral column, on the 

 other, to the subcutaneous aponeurosis. 



The dorsal interspinous bones are fourteen in number, and, 

 except the first, are flattened out, and in mutual contact at their 

 vertebral extremities, cylindrical and free in the distal half of their 

 extent. Their distal extremities are inserted into a large bolster-like 

 mass of cartilage, deeply grooved on its sides for the tendons of the 

 fin muscles. The first of the series is closely articulated to the 

 second, is pointed at both extremities, and projects a process 

 forwards which gi\es attachment to the tendon of a muscle coming 

 from the occiput. 



The interspinous bones of the anal fin, eleven in number, are 

 most of them shaped similarly to those of the dorsal fin, but are 

 much longer, and not prolonged so much between the vertebral 

 processes. Their distal extremities, which are inserted into a large 

 mass of cartilage, similar to those of the dorsal fin, are twice as far 

 removed as they from the vertebral column. The first of the series 

 is a huge shafted bone, connected at its proximal end with the 

 ha-nial spines of the first and second caudal vertebra^, and at its 

 distal end bifui'cated ; evidently, therefore, to be looked on as 

 equivalent to two interspinous bones run together. The tenth and 

 eleventh are very small, and abut against the ninth. 



There are seventeen rays in the dorsal fin, sixteen in the anal. 

 The two fins are as like one another as possible. One description 

 will suffice for both. Each ray is composed of a pair of slender 

 bones, placed one on each side of a block of cartilage. The most 

 anterior of these blocks is shoi-t and very thick, the succeeding four 

 or five get rapidly longer and are not so stout, and the remaining 

 ones dwindle quickly both in length and thickness. They are 

 closely compacted together in one firm mass. The fin rays that 

 enter into the formation of the anterior edge of the fin, end in stout 

 points, so as to make that edge unyielding ; biit the bony elements 

 of the remaining rays are prolonged beyond the cartilaginous 

 foundations, and split up into fibres which bend backwards and 

 spread in a thin fold of integument which forms the yielding 

 posterior edge of the fin. 



The structure of the tail is more remarkable still. It has eleven 

 fin rays, and as many corresponding interspinous bones, viz., five 

 superior and six inferior. The proximal extremities of the inter- 

 spinous bones approach one another, and abut on the posterior edges 

 of the ascending and descending processes of the fifteenth vertebra : 

 their distal extremities diverge, and, at the two ends of the series, are 

 in continuation with those of tlie dorsal and anal fins ; while, in the 

 middle of the series, they are in a line with the tip of the sixteenth 



