X EXPLANATION OF THE FIGURES. 



FlG. 



144. Young of the same, with its ciliated margin, magnified. 



145. Eye of the perch, containing parasitic worms (Distoma). 



146. One of the worms magnified. 



147. Transformations of the canker-worm ( Geometra vernalis] ; , the can- 



ker-worm ; ^ its chrysalis ; c, female moth ; d, male moth. 



148. Metamorphoses of the duck-barnacle (Anatifa) ; a, eggs, magnified ; , 



the animal as it escapes from the egg ; c, the stem and eye appear- 

 ing, and the shell enclosing them; d : animal removed from the 

 shell, and further magnified ; e, /, the mature barnacle, affixed. 



149. Metamorphoses of a star-fish (Echinaster sangidnolentus), showing the 



changes of the yolk (e) ; the formation of the pedicle (p) ; and the 

 gradual change into the pentagonal and rayed form. 



150. Comatula, a West India species, in its early stage, attached to a stem. 



151. The same detached, and swimming free. 



152. Longitudinal section of the sturgeon, to show its cartilaginous vertebral 



column. 



153. Amphioxus, natural size, showing its imperfect organization. 



154. Section of the earth's crust, to show the relative positions of the rocks 



composing it ; E, plutonic or massive rocks ; M, metamorphic 

 rocks ; T, trap rocks ; _L, lava. 1. Lower Silurian formation ; 2. 

 Upper Silurian ; 3. Devonian ; 4. Carboniferous ; 5. Trias, or 

 Saliferous ; 6. Oolitic ; 7. Cretaceous ; 8. Lower Tertiary or Eo- 

 cene ; 9. Upper Tertiary, or Miocene, and Pleiocene ; 10. Drift. 



155. Fossils of the Paleozoic age ; a, Lingula prima ; b, Leptsena alternata ; 



c, Euomphalus hemisphericus ; d, Trocholites ammonius ; e, Avicula 

 decussata ; f. Bucania expansa ; g, Orthoceras fusiforme ; /', Cya- 

 thocrinus ornatissimus, Hall ; j, Cariocrinus ornatus, Say ; , Melo- 

 crinus amphora, Goldf. ; /, Columnaria alveolata ; m, Cyatho- 

 phyllum quadrigeminum, Goldf. ; n, o, Caninia flexuosa ; p, Chse- 

 tetes lycoperdon. 



156. Articulata of the Paleozoic age ; o, Harpes ; b, Arges ; c, Brontes ; d, 



Platynotus ; e, Eurypterus remipes. 



157. Fishes of the Paleozoic age ; a, Pterichthys ; b, Coccosteus ; c , Dipte- 



rus ; d, palatal bone of a shark ; e^ spine of a shark. 



158. Representations of the tracks of supposed birds and reptiles in the sand- 



stone rocks. 



159. Supposed outlines of Ichthyosaurus (a), and Plesiosaurus (b). 



160. Supposed outline of Pterodactyle. 



161. Shells of the Secondary age : a, Terebratula ; b, Goniomya ; c, Trigo- 



nia ; c?, Ammonite. 



162. Supposed outline of the cuttle-fish (), from which the Belemnite was 



derived. 



163. Radiata from the Secondary age : a, Lobophyllia flabellum ; b, Litho- 



