explanation or plates 27®. 27*^. 
45 
Plate 27=. Vol I. p. 281. 
Fig. 1. Fossil fish of the genus Mlcrodon, in the family 
Pycnodonts. (Agassiz, Vol. I. Tab. G. fig. 3.) 
ig. ^ Os Vomer of Gyrodus umbilicatus, from the Great 
Oolite of Durrheim, in Baden. (Agassiz.) 
Pig. 3. Os Vomer of Pycnodus trigonus, from Stonesfield, 
Oxon. (Original.) 
Plate 27i. V. I. p, 287, Note. 
A. Teeth of a recent Shark, allied to fossil species. 
Fig. 1. Anterior and Palatal Teeth of the Port Jackson 
Shark, (Cestracion Phillippi.) (Phillip.) 
Fig. 2. Anterior cutting teeth of Port Jackson Shark, in 
the College of Surgeons, London. (Owen.) 
Fig. 3. Flat tessellated tooth of the same. Nat. size. 
a. Outer articular facet, shewing the tubular struc- 
ture of the bony base. b. Punctate surface of the 
superficial enamel. (Owen.) 
Fig. 4. Mesial, and inner articular facet of another large 
tooth of the same. a. Upper concave margin thinly 
covered with enamel, b. Lower bony margin without 
enamel, a', b. Bony base of the tooth exposed by 
removal of the Enamel. The surface is areolar, 
from the bending and blending together of the bony 
tubes, c. c'. Fractured edge of the marginal and 
superficial enamel. (Owen.) 
Fig. 5. Another anterior cutting tooth, a. Smooth ena- 
melled point, h. Minutely rugous and tuberculated 
base. In some of the cutting teeth both sides of the 
^ base are rugous. (Owen.) 
Various forms of fossil Teeth, in the three sub-fami- 
^ bes of Sharks. (B. 1. to B. 13. Agassiz.) 
•gs. 1 ^ 5 , fgggjj Sharks in the sub-family of 
Cestracionts. See V. I. p. 287. 
