In the following Plates the parts are of the
natural size, unless otherwise expressed.
PLATE I.
Various forms of teeth in fishes: the names
of the genera are subjoined to each figure.
In part Cuvier and Val,* in part original.
PLATE 2.
Fig. 1.—Head of a Myxinoid fish (Bdello-
stoma heterotrema) : a, basal pulp, supporting
b, palatal tooth; c, tongue, supporting
the lingual dental plates; d,
tendon of the great retractor muscle of the
tongue. Fig. 2. Head of Bdellostoma
hexatrema: a, palatal tooth; 6, lingual
teeth. Fig. 3. Section of head of the
Myxine glutinosa, nat. size; a, medulla
oblongata; b, cartilaginous- acoustic capsule
; c, naso-palatine canal; d, dental matrix
of lingual te e th ; e, lingual bone. Mulle
r .F ig . 4. Front view of labial and lingual
teeth of a Lamprey (Petromyzon mannas').
Fig. 5. Vertical section of the head of
the same species shewing the labial teeth :
a, the palatal cartilage supporting the
large bicuspid tooth; b, the opposing
cartilage below, representing the under
jaw; c, the lingual cartilage. Fig. 6.
A section of the persistent pulp, and
successive homy dental cones of the Lamprey.
Original.
PLATE 3.
Forms of teeth in different genera of
Sharks. Agassiz, j
PLATE 4.
The same; the view of the teeth of the
Scymms is original.
* Cuvier and Valenciennes, Histoire Naturelle des
Poissons, 4to. 1828, et seq.
t Vergleichende Anatomie der Myxinoiden, 4to. 1885,
t Poissons Fossiles, fol, 1836.
PLATE 5.
Fig. 1.—A vertical section of the under
jaw of the Lamna, shewing a vertical row
of eight teeth and their various degrees
of calcification. Fig. 2. A highly
magnified view of the primary and
secondary branches of a dentinal tube of
the tooth of a Lamna. Fig. 3. Fossil
tooth of Lamm elegans. Fig. 4. Front
view of the same tooth. Fig. 5. Fossil
tooth of an Otodus. Original.
PLATE 6.
Longitudinal section, magnified, of a fossil
tooth of Lamna elegans, shewing the ramifications
of the vascular canals in the
vaso-dentine, which constitutes the body
of the tooth: the hard or unvascular
dentine covers it like enamel. Original.
PLATE 7.
A section of the preceding tooth, magnified
500 linear times, showing the sub-
parallel dentinal tubes in the hard peripheral
layer of dentine, and the reticulate
dentinal tubes between the vascular
canals a & b. Original.
PLATE 8.
Fig. 1.—Under surface of the head of
the Saw-fish (Pristis antiquorum), showing
the rostral and maxillary teeth,
gth nat. size. Fig. 2. Some of the upper
and lower maxillary teeth. Fig. 3. A
section of the part of the rostrum and
of one tooth, a. b, ossified part of rostrum
forming its socket; c, canal for vessels
supplying the teeth; d, medullary cavity
of rostral cartilage; e, granular skin or
shagreen. Fig. 4. A single rostral tooth;
a, its posterior groove, into which the
process at the opening of the socket fits.
Fig. 5. Transverse section of the tooth.
Original.
DESCRIPTION OF THE PLATES. 9
PLATE 9.
Longitudinal section of a rostral tooth
under a low power, showing the course
and anastomoses of the vascular canals.
Fig. 2. A transverse section of the tooth,
magnified 350 linear times, shewing the
reticular dentinal tubes continued from
the vascular canals, and the clear interspaces
which define each system of canals.
Original.
PLATE 10.
Fig. 1.—Side view of the skull and teeth
of the Cestracion Philippii. Fig. 2.
Oblique view of the skull of the Monkfish
(Squatina angelus) : a, antero-supe-
rior rostral cartilage (‘ intermaxillary’ of
Cuvier); b, postero-superior rostral cartilage
(‘ maxillary’ of Cuvier) ; c, inferior
rostral cartilage (‘ premandibular’ of Cuvier)
; d, confluent maxillary and palatal
bones; e, confluent dentary and angular
pieces of the lower jaw; both figures
§ nat. size. Original.
PLATE 11.
Fig. 1.—Portion of fossil jaw with vertical
rows of six teeth of the Hybodus
grossiconus. Fig. 2. Lower jaw and
teeth of the Cestracion Philippii. Fig. 3.
Detached grinding tooth, showing the
contracted base of attachment of Cestracion.
Fig. 4. The same with a section
removed from the crown, showing the
orifices of the vascular canals. Original.
PLATE 12.
A longitudinal section of a grinding tooth
of Cestracion Philippii, magnified 150
linear, showing the general course of
the vascular canals and of the calcige-
rous or dentinal tubes which radiate
therefrom. Original.
PLATE 13.
A portion of the same section magnified
350 linear, showing the sub-parallel
tubes in the hard peripheral dentine,
and the reticulate disposition of the
tubes in the interspaces of the canals.
Original.
PLATE 14.
Five teeth in natural relative position- of an
allied extinct cartilaginous fish (Acrodus
nobilis), nat. size; and half of a vertical
section of one of the teeth, magnified 30
linear diameters. Original.
PLATE 15.
Portion of a vertical section of a tooth of
Acrodus nobilis, more highly magnified:
a, large vascular canals at the base of the
tooth; b, smaller vascular canals in the
body of the tooth ; c, calcigerous or dentinal
tubes radiating from the vascular
canals; d, the sub-parallel tubes in the
outer layer of hard dentine; e, modified
enamel. Original.
PLATE 16.
Fig. 1.— Section of a dried head of an
Eagle-ray (Aetobates Narinari). Fig. 2.
A section of the enamel and hard
dentine of the tooth of Acrodus nobilis,
magnified 400 linear times ; showing the
continuation of the fine terminal branches
of the dentinal tubes into the so-called
enamel. Fig, 3. One of the medullary
canals, with its radiating system of calcigerous
tubes, divided more or less
obliquely from the body of the tooth