450 PROF. ST. GEORGE 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 ave five small cartilages of nearly equal depth, placed side by 
side, and resting on the distal edges of the median cartilages. 
Tue Caupat Fin (Plate LX XVII. fig. 3). 
The skeleton of this fin, again, shows a great contrast between its dorsal and its 
ventral portions. Ventrally, one large hemal cartilage is attached to each vertebra. At 
first it looks as if they were slightly less in number than the vertebre; 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 heemal cartilages. Really 
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 hemal cartilages. 
THE Pectora Fin (Plate LX XVII. fig. 2). 
In the pectoral fin of this species all the three normal cartilages exist, but the middle 
one is considerably the largest. 
The metapterygium (c) is in the form of a very acute isosceles triangle, with the apex 
proximad. It gives attachment to fourteen radials. 
The mesopterygium (0) 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 pestaxial 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. 
