450 PEOF. ST. GEOR&E MIVART ON THE 



large sheet of cartilage, and by a small triangular piece attached postaxially to the 

 latter. The preaxial end of the base of the large cartilage is applied to, but is not 

 continuous with, the subjacent axial skeleton. 



The median cartilage appears as a small piece applied to the postaxial side of the 

 spine, and as three large subquadrate cartilages placed more postaxially and resting 

 upon the basal cartilages — the first two upon the large preaxial basal cartilage, and the 

 third upon the small triangular more postaxial basal cartilage. 



The distal cartilages are five small cartilages of nearly equal depth, placed side by 

 side, and resting on the distal edges of the median cartilages. 



The Caudal Fin (Plate LXXVII. fig. 3). 



The skeleton of this fin, again, shows a great contrast between its dorsal and its 

 ventral portions. Ventrally, one large haemal cartilage is attached to each vertebra. At 

 first it looks as if they were slightly less in number than the vertebrae ; a careful exa- 

 mination, however, proves that this apparent disaccordance is due only to the varying 

 degree of prolongation preaxiad of the root-portions of the haemal cartilages. Eeally 

 the correspondence in number is accurate and complete. 



Dorsally the cartilages are more numerous. There are about two to each centrum 

 preaxially, while, as we proceed postaxiad, they come by degrees to be one to each 

 vertebra. They are more inclined postaxiad distally than are the haemal cartilages. 



The Pectoral Fin (Plate LXXVII. fig. 2). 



In the pectoral fin of this species all the three normal cartilages exist, but the middle 

 one is considerably the largest. 



The metapterygimn (c) is in the form of a very acute isosceles triangle, with the apex 

 proximad. It gives attachment to fourteen radials. 



The mesqpterygium [h) is also triangular, with its acute angle proximad ; but it is 

 much broader, and the distal margin is oblique. It gives attachment to ten radials. 



The propterygium (a) is very small, but, unlike the other basals, it is broadest proxi- 

 mad. It gives attachment only to one small radial. 



The radials, except the two most preaxial ones and the three most postaxial, all 

 broaden more or less distad, and they are all once or twice segmented. With the 

 same exceptions, their apices are truncated. No radials bifurcate, even at their ex- 

 tremity ; but the bases of the five most postaxiad appear to have coalesced into a single 

 elongated cartilage which is appended to the postaxial end of the distal margin of the 

 metapterygium. 



The whole skeleton extends distad very much more on its postaxial than on its pre- 

 axial side, in spite of the greater extension distad of the more preaxial fin-rays. 



