Fig. l. Portion of the palatal teeth of Acrodus nobilis, resembling a cluster of contracted Leeches. These teeth are in their natural place, adhering to the curved granular bone of the palate, which is well preserved, and impregnated with Carbonate of lime. (Miss S. C. Burgon. Original.)

Fig. 2. Continuation of the three rows of teeth on the reverse of fig. 1. Scale one half. (Original.)

Fig. 3. One of the largest teeth on the centre row, having the upper part of the Enamel worn away by friction. Nat. size. (original.)

Fig. 4. Magnified view of the minute tubercles of Enamel which grew upon the skin; the decay of the skin [048] has brought clusters of these tubercles into contact with the bone in several parts of fig. l. (Original.)

Fig. 5. Magnified view of similar minute tooth-like tubercles of Enamel, forming the Shagreen on thc skin of the head of the recent Squatina angelus. See V. I. p. 269, Note. (Original.)