50 Fishes. 



able ill the genus Lepisosteus* of Lacepede, the bony pikes, five of 

 which inhabit the rivers of America. The Osteolepis or bony-scale 

 fish, and other fishes of the old red sandstone, seem to carry this ex- 

 traordinary character to a greater extreme. 



" We are accustomed to see vertebrated animals with the bone uncovered in one 

 part only, — that part the teeth, — and with the rest of the skeleton wrapped up in flesh 

 and skin. Among the reptiles we find a few exceptions ; but a creature with a skull 

 as naked as its teeth, — the bone being merely covered, as in these, by a hard shining 

 enamel, and with toes also of bare enamelled bone, would be deemed an anomaly in 

 creation. And yet such was the condition of the Osteolepis^ and many of its cotempo- 

 raries. The enamelled teeth were placed in jaws which presented outside a surface as 

 naked and as finely enamelled as their own. The entire head was covered with ena- 

 melled osseous plates, furnished inside like other bones, as shown by their cellular con- 

 struction, with their nourishing blood-vessels, and perhaps their oil, and which rested 

 apparently on the cartilaginous box, which must have enclosed the brain, and connect- 

 ed it with the vertebral column. I cannot better illustrate the peculiar condition of 

 the fins of this ichthyolite, than by the webbed foot of a water-fowl. The web or 

 membrane in all the aquatic birds with which we are acquainted, not only connects, 

 but also covers the toes. The web or membrane in the fins of existing fishes accom- 

 plishes a similar purpose; it both connects and covers the supporting bones or rays. — 

 Imagine, however, a webbed foot in which the toes — connected but not covered — pre- 

 sent, as in skeletons, an upper and under surface of naked bone ; and a very correct 

 idea may be formed from such a foot, of the condition of fin which obtained among at 

 least one half the ichthyolites of the Lower Old Red Sandstone. The supporting 

 bones or rays seem to have been connected laterally by the membrane ; but on both 

 sides they presented bony and finely-enamelled surfaces. In this singular class of fish, 

 all was bone without, and all was cartilage within ; and the bone in every instance, 

 whether in the form of jaws or of plates, of scales or of rays, presented an external 

 surface of enamel." — p. 99. 



" The Osteolepis was cased, I have said, from head to tail, in complete armour. — 

 The head had its plaited mail, the body its scaly mail, the fins their mail of parallel 

 and jointed bars; the entire suit glittered with enamel; and every plate, bar and scale 

 was dotted with microscopic points. Every ray had its double or treble punctulated 

 row, every scale or plate its punctulated group ; the markings lie as thickly in propor- 

 tion to the fields they cover, as the circular perforations in a lace veil ; and the effect, 

 viewed through the glass, is one of lightness and beauty. In the Cheirolepis an entire- 

 ly different style obtains. The enamelled scales and plates glitter with minute ridges, 

 that show like thorns in a December morning varnished with ice. Every ray of the 

 fins presents its serrated edge, every occipital plate and bone its sculptured prominences, 

 every scale its bunch of prickle-like ridges. A more rustic style characterized the 

 Ghjptolepis. The enamel of the scales and plates is less bright; the sculpturings are 

 executed on a larger scale, and more rudely finished. The relieved ridges, waved 

 enough to give them a pendulous appearance, drop adown the head and body. The 

 rays of the fins, of great length, present also a pendulous appearance. The bones and 



* The name is altered to Lepidosteus by Agassiz : the genus Polypterus of Agassiz 

 found in the Nile and Senegal, has similar characters. 



