449 PROF. ST. GEORGE MIVART ON THE 
The more preaxial dorsal cartilages are two in number to each vertebra. The most 
postaxial ones are, like the hemal cartilages, one to each vertebra; and in the inter- 
mediate space they pass gradually from one condition to the other. 
Both the dorsal and ventral cartilages are single and unsegmented, save as above 
mentioned, and there is neither bifurcation nor coalescence. 
The dorsal cartilages are not only much more numerous but also much inferior in 
size to the ventral cartilages. 
Tae VentRAL Fin (Plate LXXIV. fig. 5). 
This fin is supported by a series of elongated closely set cartilages, to the greater 
number of which a second (distal) cartilage is appended, there being thus a distal series 
of smaller cartilages. Proximally, all the rays but the first unite with a continuous 
thick bar of cartilage, which runs more or less antero-posteriorly and at right angles 
to the elongated cartilages which join it. 
The first ray, which is stouter than the others, does not join this bar, but is united 
with the pelvic girdle (p). 
The number of elongated cartilages is twenty; and there are seventeen distal car- 
tilages attached respectively one to each of the elongated cartilages, except the three 
most postaxiad. ‘The first seven or eight distal cartilages are of subequal length; they 
then rapidly shorten postaxiad. 
If we compare this fin-skeleton with that of the dorsal fin, the resemblance between 
its elongated and distal cartilages and the median and distal cartilages of the dorsal is 
striking. May, then, this antero-posteriorly elongated bar answer to the basal cartilages 
of the dorsal fin coalesced together? This elongated cartilage has not a slight resemblance 
to the metapterygium of the pectoral fin; and the large preaxial radial may be com- 
pared with the propterygium. 
Tue Pecroran Fin (Plate LX XIV. fig. 4). 
The pectoral limb is supported by a cartilaginous skeleton, consisting, as usual in 
Elasmobranchs, of a pro-, meso-, and metapterygium, with appended segmented rays. 
The metapterygium (c) is the largest of the three, club-shaped, and narrowing proximad. 
The mesopterygium (b) is less than half the size of the metapterygium, and acutely 
subtriangular in shape, with the apex proximad. 
The propterygiwm/(q) is a little smaller and also acutely subtriangular, but with the apex 
distad. To it is appended the most preaxial ray (or radial), which is rather wider than 
the succeeding ones, and is twice segmented, the terminal segment ending distally in a 
sharp point. The broad distal end of the mesopterygium supports the three next radials, 
each of which also consists of three segments. The terminal segment of the first of these 
three rays is also pointed distally ; but that of each of the two succeeding rays is obliquely 
truncated. All the other rays, or radials, are attached to the metapterygium, radi- 
