, 
The Fossil Elasmobranch Fishes, 369 
Again, with regard to subordinal divisions. Sir Richard Owen 
in “Paleontology” (1860), ranks the Plagiostomi as an order, 
and recognizes four families: the Cestraciontide, including the 
living Port Jackson Shark and the fossil forms supposed by Agassiz 
to be allied to it; the Hybodontide for the extinct Hybodonts; and 
the Squalide and Raiide for the Sharks and Rays. Subsequently 
(1866), he elevated these families into suborders, the Squalide 
becoming Selachii, the Raiide, Batides; and the Cestracionts and 
Hybodonts forming one suborder named Cestraphori, “in allusion 
to the presence of dorsal fin-spines.” 
In 1882 Prof. C. Hasse proposed as the result of his studies of the 
axial skeleton, a classification ‘‘based upon the varied conditions 
of the notochord and the vertebrz,” founding thereon four groups 
which he named respectively: Palgonotidani, in which the noto- 
chord is persistent; the Cyclospondyli, with partial calcification at 
intervals in the notochordal sheath, represented by the Spinacide; 
the Tectospondyli, with numerous calcified rings, comprising the 
modern Rays, with their near allies the Pristiophoride and 
Squatinide ; and finally, the Asterospondyli, in which the calcifica- 
tion is ‘‘so arranged as to appear radiating or star-shaped in vertical 
transverse section.” The author deems this classification one of much 
significance ; for the various modifications of the cranium afford no 
“satisfactory basis for the definition of subordinal groups,” and the 
types of axial skeleton defined by Hasse correspond nearly with the 
accepted divisions of the Selachii, namely, the Sharks and Rays. Thus 
the “Tectospondyli” comprise the Rays and their near allies, the 
Pristiophoride and Squatinide, while the <“ Asterospondyli ” 
include the Cestraciontide and other Sharks. Eliminating Hasse’s 
first two groups, the members of which “may be variously 
distributed” in the other two, the author, in part, accepts this 
classification and terminology as being in his view the best to 
define the subordinal divisions of the group, and which is applicable 
alike to the extinct and recent forms. This arrangement has the 
merit of being simple as well as natural. 
The numerous paleontological authorities consulted in the pre- 
paration of the Catalogue are enumerated, and the titles of their 
respective works annexed, forming a goodly list. The geological 
formations and localities whence the remains of the principalfossil 
groups have been derived are also briefly detailed. 
The teeth and bony spines of fishes and other fossil remains have 
long been known, and greatly perplexed the early observers in 
their attempts to unravel their history. Thus, the teeth of Sharks 
were described as the petrified tongues of fishes, and named Glosso- 
etre. 
i An English author early in the seventeenth century ' thus quaintly 
deseribes them :—“ Potters, in working their clay which is gotten in 
some especiall place, doe find in it certaine things which are as hard 
as stone, and of the very forme and shape of the tongues of some 
1 Richard Verstegan, A Restitution of Decayed Intelligence, 1605. 
DECADE III.—vVOL. VI.—NO. VIII. 24 
