ROOM V. GYMXODOXS PYCNODOXS. 439 



covered with small scales. The cranium and elongated jaws, 

 wjth teeth, are seen in an unique specimen in this Case ; it 

 is figured in " The Wonders of Geology," p. 349. 



Blochius longirostris. There is a fine example of this 

 Monte Bolca ichthyolite, nineteen inches long, placed near 

 the specimens of Dercetis. This genus resembles Belonosto- 

 mus in its slender muzzle and general form ; but it has brush- 

 teeth and scutcheon-like scales, as in the Dercetis; the 

 cranium with the beak measures nine inches in length. 



GYMXODOXS; SILUROIDS. Wall-case C. (No. 15, 16.) Of 

 the former family, which closely resembles the Diodons, three 

 species are found in the strata of Monte Bolca, of which there 

 are specimens in the collection. The Siluroids are related to 

 the Silurus, and a specimen from Bracklesham, formerly in 

 Mr. Dixon's collection, is placed in this Case. 



PYCXODOXS. Wall-case C. (No. 15, 16, Lower shelves.) 

 In this family of fishes the jaws are paved with rows of 

 rounded, or elongated teeth; and many of the fossil species 

 are only known by these organs. There are many beautiful 

 fossils of this kind in the Case before us. I can only direct 

 attention to several jaws, and many teeth of the genus Pyc- 

 nodus, from the Wealden and Oolite ; and to one extraordi- 

 narily perfect lower jaw of an allied genus Gyrodus, on the 

 middle Shelf: it is labelled "from Poulshot, near Devizes : " 

 every tooth is as perfect as when recent. 



We now proceed to the examination of the Ichthyolites of 

 the next order; the Ctenoids, occupying the compartments of 

 Nos. 17 to 20 inclusive, in Wall-case C; the Cycloids, Cases 

 C and D, and the Placoids, in the Table-cases Nos. 2, 4, 6, 8, 

 10, and 12 (see ante, p. 410), will also be included in the 

 same division of the present Chapter. 



1 See " Medals of Creation," p. 650. 



