536 MR. A. S. WOODWARD ON [ Dec. 7, 
ment. The latter (mtp) is triangular in form, and elongated antero- 
posteriorly ; the foremost border abuts against the hinder edge of 
the preaxial cartilage, which it equals in transverse extent ; and the 
inner border curves gradually outwards and backwards to meet the 
nearly straight external boundary ata posterior apex. Judging from 
the analogy of living Selachians with fins of a similar type, the 
posterior of these cartilages may be regarded as the metapterygium ; 
while the anterior element may represent the coalesced pro- and 
mesopterygium (as in Pristiophorus'), or it may be wholly meso- 
pterygial, with a minute, indistinguishable propterygium at its 
proximal angle (as in Heptanchus and Hexanchus*). 
Beyond the basal cartilages are arranged the cartilaginous rays of 
of the fin (7). These are somewhat obscured both in front and 
behind by remains of the integument, and it is uncertain whether 
the first attached to the preaxial element is stouter than the remainder; 
twenty rays, however, can still be counted on the right side, and 
there are traces of sixteen on the left; the foremost thirteen are 
directed almost transversely or outwards, while the following have a 
more marked backward inclination. 
The pelvic girdle and its appendages are rather more satisfactorily 
displayed than the pectoral structures just described. Anteriorly, 
on each side, the cartilage is prolonged into a remarkably strong 
prepubic process (p.pb), the base of which occupies one fourth of 
the entire breadth of the girdle; but the forward extent of the 
prominence is not determinable, owing to imperfect preservation. 
Posteriorly, on each side, is a long slender iliac process (2), especially 
well seen on the left, and slightly directed outwards ; itis much less 
robust than the prepubic, and appears of almost uniform breadth 
throughout ; in length it equals twice the width of the transverse 
pubic cartilage (pub). Arising immediately within the point of 
union of the pubic and iliac regions is the basal cartilage (5.8) of 
the pelvic fin, which exhibits no sutural divisions, and (this specimen 
being a male) is prolonged backwards into a powerful clasper (cl). 
It curves gradually inwards throughout the whole of its rayed portion, 
and is of almost uniform breadth. On passing into the claspers, 
the cartilage becomes more calcified, and perhaps slightly broader. 
The inner edge is straight, but the outer edge exhibits a gentle 
sigmoid curve, which results in the widening of the rounded terminal 
extremity ; and at the end of each clasper (especially the left) a 
smal] tuft of dermal hooklets (A/) is preserved. The fin-rays (7), 
which appear to be completely shown on the right, are altogether 
twelve in number, and the length of the supporting cartilage is 
scarcely more than one half of that of the appended clasper. There 
is no distinct evidence of one or more preaxial rays attached to the 
girdle itself, and the foremost exhibited is no longer than the 
remainder. 
1 St. G. Mivart, “ Fins of Elasmobranchs,” Trans. Zool Soc. yol. x. p. 403, 
pl. Ixxviii. fig.1. 
* C. Gegenbaur, “Schultergiirtel der Wirbelthiere, und Brustflosse der Fische,” 
Untersuch. yergl. Anat. Wirb. 18665, pl. ix, figs. 1, 2. . 
