EXPLANATION OF PLATE 27^ 47 



A double row of similar hooks occurs on the first 



dorsal ray of the Barbel, (Barbus Vulgaris.) And 



on the anterior ray both of the dorsal and anal fins 



of the Carp, (Cyprinus Carpio.) 



Fig. 4. Transverse section of fig. 3, at a,* (De la Beche.) 



Plate 27 ^ V. I. p. 288. 



Fig. 1. 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 



* In the Lond. and Edin. Phil. Mag. Jan. 1836, the author has 

 published a notice of his recent discovery of the jaws of four extinct 

 species of fossil fishes of the genus Chimaera, a genus hitherto un- 

 known in a fossil state. The only known species (C. monstrosa) 

 approximates most nearly to the family of Sharks ; and is found 

 pursuing Herrings and other migratory fishes. The Chimaera is one 

 of the most remarkable among living fishes, as a link in the family of 

 Chondropterygians ; and the discovery of a similar link, in the geo- 

 logical epochs of the Oolitic and Cretaceous formations, shews that 

 the duration of this curious genus has extended through a greater 

 range of geological epochs, than that of any other genus of fishes yet 

 ascertained by Professor Agassiz, and leads to important considera- 

 tions in Physiology. 



The Chimaera partakes of one remarkable character with the Ces- 

 tracion Phillippi, whereby this species alone, among living Sharks, 

 is connected with the extinct forms of that family, in having the first 

 ray of the dorsal fin enlarged into a strong bony spine armed with 

 sharp hooks, like the Ichthyodorulite of the earliest fossil Sharks. 



