632 MR. A. SMTTH -WOODWARD ON SOME [NoV. 18, 



pet. )is not completely known, but its rays clearly exhibit the characters 

 just described. Its supporting elements are attached to a long, 

 slender, gently arched clavicle, externally marked with delicate, irre- 

 gular longitudinal striations ; and there is a large supraclavicle above 

 this, adjoining the truncated angle of the operculum (s.cl.), broad 

 above, tapering below, and transversely marked with numerous, closely 

 arranged coarse rounded rugae of ganoine. The dorsal and anal 

 fins are precisely opposed, not far from the caudal extremity, as 

 shown in Plate LV. fig. 9, and the lobes of the deeply forked caudal 

 fin (Plate LV. fig. 10) seem to be obtusely pointed, with a convex pos- 

 terior-inner border, of which the subdivisions of the branched rays 

 are extremely numerous and delicate. There are indications of 

 minute fulcra on each of the median tins. 



Squaniation. — The squamation is continuous, and all the scales are 

 thick and bony, with a superficial layer of ganoine. They are shghtly 

 imbricating, and the posterior border is either smooth or feebly 

 crimped. Except quite at the extremity of the tail, the greater part 

 of the flank is covered by a single very deep longitudinal series of scales, 

 along the upper part of which extends the lateral line, as indicated by 

 the row of short transverse ridges by which its course is marked. In 

 the anterior part of the trunk, one of these scales is between five and six 

 times as deep as broad, abruptly truncated below, but somewhat tapering 

 and slightly reflexed forwards above the position of the lateral line. On 

 the inner face of the scale there is a vertical median ridge, terminating 

 above in a feeble articular peg, and excavated below by a small socket. 

 Into the latter fits the upper articular peg of another scale, two and 

 a half times as deep as broad, which is slightly overlapped by the 

 principal flank-scale, and is similarly strengthened by a prominent 

 ridge within. The ventral margin is completed by three or four 

 small scales, one above the other, as broad as those above, but having 

 an extremely short vertical measurement. There are no indications 

 of ventral ridge-scales. At the upper end of each principal flank-scale 

 there occurs a rhomboidal scale scarcely twice as deep as broad, having 

 a slight oblique ridge about its middle (Plate LIV., Plate LV. figs. 

 7, 8). Another nearly similar but less deep scale adjoins the anteriorly 

 directed upper border of the latter ; and a small azygous ridge-scale 

 (Plate LV. fig. 8, r.), irregularly sexangular, narrower in front than be- 

 hind, completes the vertical series above. The writer has not observed 

 any peg-and-socket articulation in these upper scales, and it is prob- 

 able that their borders simply overlap. Towards the caudal region 

 (Plate LV. figs. 9, 10) the depth of the principal flank-scales becomes 

 relatively less, while the very narrow ventral scales are more nearly 

 equilateral ; at the extremity of the tail, indeed, all the scales are 

 diamond-shaped and of nearly uniform dimensions. The scale orna- 

 ment varies considerably in different individuals and upon different 

 parts of the body, but it is essentially similar to that of the external 

 head and opercular bones already described, though perhaps less 

 prominent. In small (probably young) specimens, both the bones 

 and scales are very feeljly ornamented, liut in fully grown individuals 

 the rugose ganoine is always conspicuous. Each scale of the two 



