688 



GEOLOGY. 



colour to be owing to the presence of phosphate of iron, which has communicated a similar 

 tint to the fishes of the Caithness schist. The teeth of Coccosteus, instead of being fixed 

 in sockets, are integral portions of the bone, like the teeth of a comb ; and the mouth 

 is supposed to have been placed vertically, which, if proved to be correct, is an anomalous 

 construction. The mouths of Crustacea, as the crab and lobster, open vertically ; but 

 naturalists have hitherto found it an invariable condition of vertebrata, that the position 

 of the jaws is horizontal. 



Pterichthys. The first individual of this genus winged-fish which embraces 

 several species, was discovered by Mr. Miller, who remarks, upon finding the prize "I 

 fain wish I could communicate the feeling with which I contemplated my first-found 

 specimen. It opened with a single blow of the hammer ; and there, on a ground of light- 

 coloured limestone, lay the effigy of a creature fashioned apparently out of jet, with a 

 body covered with plates, two powerful-looking arms articulated at the shoulders, a head 

 as entirely lost in the trunk as that of the ray or the sun-fish, and a long angular tail. 

 My first-formed idea regarding it was, that I had discovered a connecting link between 

 the tortoise and the fish ; the body much resembles that of a small turtle ; and why, I 

 asked, if one formation give us sauroid fishes, and another give us chelonian ones, or if 

 in the lias we find the body of the lizard mounted on the paddles of the whale, why not 

 find in the old red sandstone the body of the tortoise mounted in a somewhat similar 



manner ? The 

 in error, but as 

 which not many 

 have corrected 

 may be deemed 

 one." Upon submitting several 

 wrote in reply : "As to your 

 here (London), except that they re- 

 meuts of some of the Caithness 

 can be referable to any reptile ; for 

 approach to crustaceans than to any 

 that Agassiz will pronounce them 

 the curious genus Cephalaspis of 

 connecting links between crust a- 

 anticipated from the Swiss 

 him. The form of Pterichthys, 

 a rough resemblance to that of 

 extended, the body narrowing, and 

 the centre of the trunk, gradually 

 species of the genus found in this 





idea originated 

 it was an error 

 naturalists could 

 at the time, it 



""'" an excusable 



specimens to Sir R. Murchison, he 

 fossils, we know nothing of them 

 mind me of the occipital frag- 

 fishes. I do not conceive they 

 if not fishes, they more closely 

 other class. I conceive, however, 

 to be fishes, which, together with 

 the old red sandstone, form the 

 ceans and fishes." The verdict 

 naturalist was pronounced by 

 which is here restored, bears 

 a headless man, with his arms 

 terminating in one leg fixed in 

 tapering down to a point. The 

 country are all small, not longer 



Pterichthys. 



than eight or ten inches ; but examples of the lateral spines have been discovered in 

 Russia, exceeding a foot in length, which must have belonged to enormous individuals. 

 These spines were not intended for locomotion but defence, lying close by the creature's 

 side when in a state of security, and erected upon the intimation of danger, as in the 

 case of the common river bull-head, which has similar spines. The Pterichthys are 

 however commonly found with the spines extended, proclaiming the alarm under which 

 existence terminated, and the instinct of self-preservation, which now marks all living 

 organisms, then in action, but exerted in vain. 



Holoptychius. This genus has been so named from the character of the scales, which 

 present undulating folds or furrows upon an enamelled surface. The scales have been 

 found exceeding three inches in length by two and a half in breadth, indicating the great 



