1886. } SQUALORAJA POLYSPONDYLA. 637 
AFFINITIES AND Sysrematic Position. 
Proceeding, lastly, to a consideration of the systematic position of 
Squaloraja, it will be observed that the new fossils here described 
enable us to arrive at a much more definite conclusion than it has 
hitherto been possible to formulate. Agassiz has pointed out the 
affinities of the genus with the Pristiophoridw; Davies has further 
indicated some resemblances to the Rhinobatide, and been led, by 
his discovery of the rostral spine, to speculate at least as to its 
family distinctness ; while Ginther! has likewise refrained from 
more than a suggestion that it is nearly allied to the first-named 
group. 
That the animal is a true Selachian, there cannot be the slightest 
doubt ; nor does it require more than a superficial glance to recognize 
its resemblance both to the Sharks proper and the Rays. But (as 
already mentioned by Davies) the possession of a prehensile rostral 
spine by the male distinguishes Sgualoraja from all known members 
of the order, recent or fossil, and suggests affinities with the Chi- 
meeroids* ; while the enormous size of the barbels or cirri seems to 
have no parallel, at least among living forms. The dentition, too, 
is evidently unique, so far as our present knowledge extends, and 
the marked character of the symphysis is a feature of peculiar 
interest. 
Comparing the genus in other points with the various recognized 
families upon the “‘ borderland ” of the two sections of the Selachii, 
reference may first be made to the Rhinide. 
Though agreeing with this group in the very slight depression of 
the body, it is readily distinguished by the elongation of the snout 
and the inferior position of the mouth; and the anterior border of 
the pectoral fin is much less produced forwards, owing to the relatively 
smaller size of the propterygium. 
To the oft-mentioned Pristiophoride, Squaloraja bears a remark- 
able resemblance, both in the structure of the snout and the general 
form of the body; but there are no traces of teeth on either 
boundary of the rostrum ; and if the peculiar dental armature of 
the jaw may be quoted asa family character, this, too, will exclude 
the genus from the present group. 
From the family of Pristide, the Liassic form is still further 
separated by the characters of the head and its anterior prolongation, 
though agreeing tolerably well in the shape of the trunk and fins. 
There are also certain features that prevent its reference to the 
Rhinobatide. The structure of the pectoral fin in this family is quite 
distinct from that of the fossil, the propterygial element being pro- 
longed far towards the head, so that in some cases it is connected by 
skin with the cephalic region. 
Its distinctness from other families is too obvious to require any 
special mention, and Sgualoraja is thus excluded from all recognized 
divisions of the order. It may even represent a hitherto unknown 
' A. Giinther, ‘Study of Fishes’ (1880), p. 835. 
2 We regard the Chimeroidei as a distinct order, follow ing Professor Huxley, 
Proe. Zool. Soc. 1876, p. 57. 
