o19, DESCRIPTION OF A NEW SPECIES OF SHARK. 
situated midway between the tip of the snout and the 
anterior gill-opening. Spiracles large, opening behind the 
upper half of the eye, with a moderate intervening space. 
Mouth small and transverse, with the lateral groove very 
broad and deep. Upper jaw with a patch of small, conical, 
curved teeth anteriorly, consisting of about four irregular 
rows; a single series of much larger, erect, compressed, 
minutely serrated, scalpriform teeth in the lower jaw. Gill- 
openings small, the posterior one pierced immediately in 
front of the base of the pectoral fin. The first dorsal 
commences above the middle gill-opening, and rises by a 
continuous and equal gradation to the spine, its outer margin 
being straight; behind the spine the rise is much more 
abrupt, and the contour is slightly convex with the tip 
rounded; the posterior margin is deeply concave; the height 
of the fin beneath its extremity is equal to the distance be- 
tween the anterior gill-opening and the tip of the snout, that 
of the spine equal to the head in front of the spiracle; the 
spine is situated in the anterior portion of the last fourth of 
the base of the fin, is perfectly straight, with a slight in- 
clination forwards, and protrudes a short distance beyond 
the membrane; its base is exactly midway between the tip 
of the snout and the origin of the caudal, while tbe distance 
between the bases of the two dorsal spines is but little more 
than the length of the base of the first dorsal in front of its 
spine, and five-sevenths of the length of the fish in front of 
it; the intradorsal ridge is very strongly developed; the 
second dorsal has a general resemblance in shape to the 
first, but is not so large; the upper margin is more regularly 
even, and the extremity, which is much more pointed, hangs 
vertically above the base of the caudal, instead of falling 
within the vertical from its own base, as with the anterior 
fin; the length of its base is equal to that of the intradorsal 
_ space, and to the height of the fin beneath its tip, and is 
four-sevenths of the outer margin; the spine is situated in 
the latter portion of the anterior half of the fin, and is gently 
curved backwards throughout its entire length; in height it 
is but little less than that of the first dorsal; the pectoral fin 
is well developed and pointed, its length equal to the space 
which divides its anterior basal margin from the nostril; the 
distance between its base and that of the ventral is two-fifths 
longer than that between the dorsal spines, and is traversed 
by a strongly developed lateral ridge; the ventral fin com- 
mences beneath the spine of the second dorsal, and the 
distance between its termination and the origin of the lower 
caudal lobe is equal to that between the second dorsal and 
the caudal fin; the caudal lobes are well developed; the 
outer margin of the upper lobe is straight, the angle and 
