NATURAL HISTORY OF THE PRIMEVAL WORLD. 



19 



separate pieces, in the same way lliat several thin pieces 

 of steel arc set together in the springs of carriages. 



Tlie reptile's short thick neck was continued back- 

 wards, from behind the e}'es, in a vertebral column of 

 more than one hundred vertebrie. As it was adapted, 

 like the whale, for rapid motion through the sea, its 

 vertebrae did not possess the invariable solidity of those 

 of the crocodile, but rather the structure and lightness 

 of those of fishes. The section of these vertebraj 

 presents two hollow cones, connected with the centre 

 of the vertebrre by their summits only, so as to permit 

 the utmost flexibility of movement. " Between these 

 hollow vertebrre a soft and flexible intervertebral sub- 

 stance, in the form of a double solid cone, is so placed 

 that each hollow cone of bone plays on the cone of 

 clastic substance contained within it, with a motion in 

 every direction, thus forming a kind of universal joint, 

 and giving to the entire column great strength and 

 power of rapid flexion in the water. But as the 

 inflections in the perpendicular direction are less 

 necessary than in the lateral, they are limited by the 

 overlapping, or contiguity of the spines. This mode 

 of articulation gives mechanical advantage to animals 

 like fishes, whoso chief organ of progressive motion is 

 the tail, and the weight of whose bodies, being always 

 suspended in water, creates little or no pressure on 

 the edges, by which alone the vertebrae touch each 

 other." 



The ribs were slender, most of them bifurcated at 

 the top, and extended along the entire length of the 

 vertebral column, from the head to the pelvis. 



As the Ichtlvjosaurus was a massive animal, it 

 required the means of facile descent and ascent in the 

 water. Tliis was provided by the construction of its 

 anterior paddles, wliich were half as large again as the 

 posterior, and by tlie no less extraordinary combina- 

 tion of bones that formed the sternal arch, or that part 

 of the chest on which these paddles rested. 



It has been remarked as a curious fact that this 

 structure is found repeated in the ornitliorhynchus of 

 New Holland, an animal presenting the anomalous 

 combination of a furred, duck-billed quadruped, with 

 four webbed feet, suckling its young, and most pro- 

 bably ovoviviparous, which dives to the bottom in 

 quest of food, and returns to the surface to breathe the 

 air. In this living animal the Divine Maker appears 

 to have repeated the organic contrivances which lie 

 had originally designed for the Iclithyoscmrus ! 



To enable the animal to move in the water, both its 

 anterior and posterior extremities were converted into 

 fins and paddles, which must have much resembled 

 externally the undivided paddle of a porpoise or 

 wdiale. Internally the difference was considerable. 

 The phalanges of the fingers were made up of ninety 

 to one hundred polj'gonal bones. A specimen of the 

 posterior fin of the Iclithyoscmrus comrminis, discovered 

 at Barrow-on-Soar, in Leicestershire, in 1840, exhibited 

 on its posterior margin the remains of cartilaginous 

 rays, which bifurcated towards the edge, like those in 

 the fins of a fish. It had previously been supposed, 

 remarks Professor Owen, that the locomotive organs 

 were enveloped, while living, in a smooth integument, 

 like that of the turtle and porpoise, which has no other 



support than is afforded by the bones and ligaments 

 within ; but it now appears that the fin was much 

 larger, expanding far beyond tlie osseous framework, 

 and deviating widely in its fish-like rays from the 

 ordinary reptilian type. It is the opinion of our great 

 comparative anatomist that these stifl'-necked Saurians 

 were furnished, in addition to the anterior paddles, 

 with a tail-fin, possessing no radiating bones, and purely 

 tegumentary, whicli expanded vertically to assist them 

 in turning, and not horizontally, as in the whale. 



The teeth of the Ichthyosaurm are conical, ami 

 resemble those of the crocodile, but are considerably 

 more numerous, amounting in some individuals to a 

 hundred and eighty. Tliey vary in each species. Not 

 inclosed in deep and separate sockets, like those of the 

 crocodile, they bristle along one continuous furrow of 

 the maxillary bone, where the rudiments of a separa- 

 tion into distinct alveoli (or cavities) may be detected 

 in slight ridges extending between the teeth, on the 

 sides and bottom of the furrows. The contrivance by 

 which the old teeth give place to new is analogous 

 in the Ichthyosauri to that existing in the crocodiles. 

 In both the young tooth begins its growth at the base 

 of the old one, whore, by pressure on the side, it causes 

 first a partial absorption of the base, and, finally, a 

 total removal of the body of the older tooth which it 

 is intended to replace. 



From their predatory habits these huge reptiles of 

 the secondary epoch were exposed to frequent loss of 

 teeth ; but as we have seen, an abundant provision was 

 made for their renewal. 



These details will suffice to convince our readers 

 that they were animals potently armed citiier for 

 attack or defence. Whether their skin was smooth 

 like that of the whale, or covered with scales like that 

 of the crocodile, we cannot absolutely determine" but 

 it is probable that tlie former condition existed. 



Popularly speaking, we may saj', with Bayle, that 

 the Ichtliyosaurus was the whale of the Saurians, the 

 Cetacean of the primeval seas. " It was, in fact, an 

 animal exclusively marine, which on shore would rest 

 motionless, like an inert mass: its whale-like paddles 

 and fish-like vertebrre, the length of the tail, and other 

 parts of the structure, prove that its habits were aquatic, 

 while tlie remains of fishes and reptiles (discovered in 

 its intestines), and the form of its teeth, show that it 

 was carnivorous. Like the whale, also, the Ichthyo- 

 saurus breathed atmospheric air ; so that it was under 

 the necessity of coming frequently to the surface of the 

 water, like that inhabitant of the deep." We can even 

 believe, with Bayle, that it was provided, like the 

 whale, with vents, or blowers, through which it ejected, 

 in columns into the air, the water it had swallowed. 



The Liassic formations whicli occur in Dorsetshire, 

 in the vicinity of Lyme Regis, have long been famous 

 among geologists for the fossil treasures which they 

 have yielded to the persevering inquirer. Their 

 quarries form the cemetery of the Ichthyosauri, 

 the sepulchre which has long entombed those strange 

 creations of the ancient seas. It was in 1811 that 

 Mary Anning, a young peasant woman who gained a pre- 

 carious livelihood by collecting fossils, first discovered 

 the Ichthyosaurian skeleton. She hired workmen 



