4 BULLETIN OF THE 
a similar point on the anal fin. Both upper and lower (anterior and 
posterior) margins are curves, which meet in the apex (Plate XIII.). 
Pectorals, ventrals, anal and caudal are large. The pectorals are 
moderately long ; both front and hinder margins are curved — the lat- 
ter most strongly, and the curves meet in a blunt angle at the end of 
the fin, which is nearer the front edge. The ventrals are placed some 
distance behind the middle of the total length. They are a little larger 
than the pectorals, the reverse of what is usual among sharks. Each is 
broadly rounded, being about twice as long as wide, and ends in an 
acute point behind the vent (Plates I. and XII.). In length the anal fn 
approaches eight inches, and in depth it is close upon three. The curve 
of the lower margin is tolerably regular and sharp. An acute angle is 
formed by the posterior extremity. 
The tail is without a pit at its root, and the fin is not divided into 
lobes by a notch in its lower border. Rising very gradually from a point 
opposite the beginning of the lower part, the upper portion of the caudal 
fin reaches in its greatest height not more than three eighths of an inch, 
and is continued downward behind the end of the vertebral column to 
form more than half of the posterior border, as is proved by the changes 
in direction in fibre, shagreen, and armature on the edge. The lower 
portion of the fin lacks little of three and a half inches in its greatest 
width, and, with the filamentary extremity, is not far from twelve inches 
in length. Not a trace of the caudal notch is to be found. At its 
widest, the tail is a little less than half as wide as long. Its shape is 
better shown in Plate XIV. than in Plate I. 
The Teeth. 
Plate VI. Figs. 1-8. 
As there are fifty-one rows and six teeth in each row, the whole 
number of teeth in function at once amounts to three hundred and six. 
In this the soft one at the inner end of each row is not counted. Ina 
general way a tooth may be described as three long, slender, very sharp, 
subconical cusps, separated by a pair of rudimentary denticles or but- 
tons, on a broad backward extended base. Variation according to posi- 
tion on the jaw makes it necessary to modify the description for teeth 
of the different series. All of the teeth are small; the largest of them 
is hardly a quarter of an inch in width across the tips of the cusps, and 
the smallest is less than one sixteenth. On the upper jaw there are 
thirteen rows on each side; on the lower, there are twelve on each side 
