I C H 



[227] 



I C H 



lizard and a fish. The name ap- 

 pears to have been given to it by 

 M. Konig. The genus comprises 

 many species ; some of these attain 

 a magnitude not inferior to that of 

 young whales. The head of the 

 ichthyosaurus resembled that of a 

 dolphin, its teeth were conical, 

 sharp, and striated, and exceeding- 

 ly numerous, in some cases amount- 

 ing to nearly two hundred, not 

 enclosed in separate sockets, but, 

 as in the crocodile, ranged in one 

 continuous groove, or furrow, of 

 the maxillary bone ; as also in the 

 crocodile, abundant provision was 

 made for replacing the old teeth, 

 as they were lost, -by a supply of 

 new ones. The eye was of enor- 

 mous magnitude, the orbit in some 

 instances measuring fourteen inches 

 in its longer diameter, and Prof. 

 Buckland states, " We have evi- 

 dence that it possessed both micro- 

 scopic and telescopic properties. 

 The bony sclerotic of the ichthyo- 

 saurus approaches to the form of 

 the bony circle in the eye of the 

 Golden Eagle ; one of its uses being 

 to vary the sphere of distinct 

 vision, in order to descry their prey 

 at long or short distances. The 

 soft parts of the eyes of the ichthy- 

 osaurus have, of course, entirely 

 perished; but the preservation of 

 this curiously constructed hoop of 

 bony plates, shows that the enor- 

 mous eye, of which they formed 

 the front, was an optical instrument 

 of varied and prodigious power, 

 making this marine saurian to 

 descry its prey at great or little 

 distances, in the darkness of night 

 and in the ocean's depths." The 

 beak was that of che porpoise ; the 

 teeth, as before mentioned, those 

 of the crocodile. In order to de- 

 monstrate the close relation between 

 the ichthyosaurus and the lacerta 

 family, it is desirable to state, that 

 the lower jaw in that family, in- 

 stead of having, like other quadru- 



peds, a single bone on either side, 

 exhibits not fewer than six of these ; 

 one called the dental, which carries 

 the teeth, forms the whole anterior 

 extremity of the jaw, and continues 

 to cover the upper portion, and to 

 lap over the exterior; the rest of 

 the outer face is formed, in the 

 posterior part by a second bone, 

 the coronoid ; the bottom by a 

 third, the angular ; and the inner 

 face by a fourth, the opercular : in 

 addition to these four bones, the 

 articular, which is placed at the 

 posterior extremity for the purpose 

 which its name denotes, and a small 

 crescent-shaped bone, which some- 

 times forms the coronoid process, 

 complete the stated number. Of 

 these bones, the five first have been 

 proved to have been possessed by 

 the Ichthyosaurus, occupying situ- 

 ations closely corresponding to 

 those which they possess in the 

 crocodile. The crescent- shaped 

 bone is the only one of the series 

 not yet detected. The vertebrae 

 nearly resembled those of the shark, 

 being hour-glass shaped, and hav- 

 ing both faces of their body deeply 

 concave as in fishes ; the vertebral 

 column was composed of more than 

 one hundred pieces ; the ribs were 

 slender, and the majority of them 

 bifurcated, or forked, at the top; 

 the bones of the sternum were 

 strong and largely developed, and 

 combined nearly in the same man- 

 ner as in the ornithorynchus or 

 platypus. The ichthyosaurus had 

 four paddles, the form of its ex- 

 tremities deviating from the sau- 

 rians and approaching the mam- 

 malians, being converted from feet 

 into fins; these fins, or paddles, 

 were composed of numerous bones 

 enclosed in one fold of integument ; 

 the fore-paddle was composed of 

 nearly one hundred bones, and like 

 the mammalians it possessed a hu- 

 merua, or shoulder bone, a radius 

 and ulna, or the bones of the fore 



