364 
Plate XXXI. 
Taniwhasaurus oweni, Hector. 
A, B. Portion of head and lower jaw. (No. lle, one-fourth natural size.) 
A, upper surface of cranium ; A’, side view of the ваше; B, fragment of the lower 
jaw, seen from above, and restored to its proper position relative to the cranial frag- 
ment; B’, lower jaw seen from the right side. These bones are much broken, and the 
drawing of the lower jaw is to some extent a restoration. 
C. Paddle bones. (No. 115, one-fourth natural size.) 
A vein of ealespar, whieh is shown in the drawing, passes through the ulna and 
across the articulations with the humerus above and the carpal below. In the slab the 
radius has been displaced from its proper position, but has been restored in the drawing, 
and fits exactly with the other bones into its position. On the same . 81а, but not 
connected with paddle bones, are fragments of ribs and of a smooth, radially-striated 
pelvic (?) bone, not represented on the plate. 
DESCRIPTION oF PrATES XXIV.—XXVI. 
Plate XXIV.—A (a). Inner parapet of dentary bone of Leiodon. (b). Outer parapet 
of dentary bone. (c). Floor of dentary bone. (d). Cementing alveolus. (е). Dental 
fossa. (J). Primitive tooth. (g). Successional tooth. 
A' Side view of the same specimen. 
B Transverse section of middle of crown of tooth. 
C Base of tooth with surrounding alveolus, showing at (a) the encroachment of the 
gene tooth. 
D Tooth from which the microscopic preparations were taken, showing the 
absorption 2 the alveolus at (a), where the successional tooth has forced its way out. 
E Section of tooth showing the radiating caleygerous tubuli and the concentric 
contour lines. 
F Section of tooth showing the caleygerous tubuli ; the portion from (a) to (b) might 
be considered the enamel, if really any such distinct layer exists in the teeth of the 
Leiodon. 
G (a, b, c). Tooth of Mauisaurus ? 
H (a, b). Tooth of Plesiosaurus traversii. 
Plate XX V.— Section showing tooth, alveolus, and jaw-bone of Leiodon ; the initis 
of the latter not very distinctly seen in the fossil. (а). Cementing alveolus. (б). Outer 
parapet of dentary bone. (c). Coronoid bone. (d) Descending process of dental. 
(4). Angular bone. (e) Opercular bone. (7). Inner parapet of dentary bone. (g). Floor 
of dentary bone. (л). Pulp-cavity. 
Plate XXVI.—A Section showing tooth of Leiodon, with channel communicating 
through the cement to the surface of the dentary bone. 
C Sections of the jaw of an allied form to Leiodon —Á The 
lines xY should be vertical. 
