1886. ] SQUALORAJA POLYSPONDYLA. 535 
Vertebral Column.—In the subject of fig. 1 the vertebral column 
is beautifully shown beyond the shoulder-girdle, though somewhat 
imperfect in front. As already described by previous writers, the 
vertebree (fig. 8) are merely slender, concentrically marked rings, of 
the truly “‘ tectospondylic ’’* type, and in the space just mentioned 
no less than 340 can be counted; in the abdominal region, sixteen 
of these occupy the length of a centimetre, while in the tail the 
proportions are so slightly different that only one more ring is com- 
prised within the same distance. The obscure portion in front of 
the pectoral girdle measures one and a half centimetres in length, 
probably representing about 24 vertebre ; and if three centimetres 
are missing from the end of the tail*, this loss will indicate an 
additional 48. The total number is thus found to be approximately 
400, as estimated by Davies in the large specimen described in 1872. 
In the more aged individuals (e. g., no. [I.) the vertebral rings 
are more robust than those of the apparently yonng (e. g., no. III.) ; 
and it is remarkable that in no example is there any trace of the 
fusion of the elements in the region of the neck. 
But it is not necessary to add a detailed account of the structure 
of the vertebra themselves, for they have already been carefully 
examined and described by no less an authority than Professor Carl 
Hasse, of Breslau®. As the result of his researches in this direction, 
the latter anatomist concludes that in Squaloraja ‘‘ we have to do 
with an ancestral form of the now living Pristidee, a form which, in 
its development, appears to have advanced beyond the existing Pris- 
tiophoridze, and also beyond the oldest Rhinobatidz,”’ which be has 
deseribed from the upper Oolite of Bavaria. 
The vertebral arches were not of sufficient consistency to leave the 
slightest trace in the fossil state. 
Appendicular Skeleton.—In the subject of fig. 1, as already 
remarked, the pectoral fins are sufficiently well preserved to exhibit 
their complete severance from the cephalic region and their corre- 
spondence in general character to those of the living Pristiophorus. 
But the remains of the supporting girdle are much less perfect and 
satisfactory, and the other known specimens do not appear to throw 
any further light upon the subject. There can be little doubt, how- 
ever, that the “‘ girdle’ was complete, as in the Rays proper, and the 
well-defined cartilage (s.sc) on the right is evidently the character- 
istic suprascapula. A faint trace of the posterior boundary of the 
transverse coracoid bar (cor) is also shown on the same side. 
The proximal cartilages of the fin are only two in number, and 
well preserved on both sides of the fossil, though most completely 
displayed on the left. The preaxial element (pms) is elongated in 
a transverse direction, and appears of almost uniform breadth, though 
its exact shape is evidently destroyed by crushing ; it is relatively 
small, having only about one quarter the size of the postaxial ele- 
1 ©. Hasse, ‘Das natiirliche System der Elasmobranchier,’ allgemeiner 
Theil (1879), p. 44. 
? The caudal region of the fossil is not completely shown in fig. |. 
°C. Hasse, “ Hinige seltene palaontologische Funde,” Paleontographica, 
vol. xxxi. (1885) p. 4, pl. i. figs. 2, 3. 
