and on the Geological Posiliun of their Fossil Remains. 451 



It is probable that if other anatomists have sought for this 

 representation of the entire body in the head alone, they may 

 have imagined other relations, and it is by no means my inten- 

 tion to follow them in this branch of their researches. 



The circle in which I confine myself is akeady vast enough 

 to admit of our taking widely different routes, according to 

 the point from which we may each set out. This desire of 

 finding a representation of the body has constrained some 

 authors to assign to a particular bone, in Reptiles or in Fishes, 

 a denomination which they probably would not otherwise have 

 thought of; and a predilection for discovering the osseous parts 

 and proportions in a uniform number, has been the means of 

 forcing others into deviations not less strange. When their 

 calculations were foiled in the investigation of those bones in 

 which it seemed natural to expect they might be exhibited, 

 they found themselves necessitated to have recourse to the 

 neighbouring ones; sometimes to admit of singular transfers, 

 returnsj and conversions, more or less complete, without re- 

 gard to the innumerable organs and soft parts which it would 

 be necessary to displace and otherwise to dispose of, in order 

 to connect a single bone in one situation with another near it; 

 — to insert, for example, a part belonging to the sternum be- 

 tween two other parts belonging to the os hyoides, or to efl^ect 

 such other transposition as might bear to be explained as a 

 simple formation. 



The examples of these varieties of ideas, already very nu- 

 merous, relative to the Reptiles, of which I shall have to speak, 

 might have been multiplied almost infinitely, if the limits of 

 my work had permitted me to follow these anatomists and 

 their sagacious emulators into the class of Fishes, and to 

 discuss solel}' the several opinions which they have proposed 

 on the constituent parts of the opercula*, and on the os hj-- 



oides. 



tympanum is the ischium ; llic condyloiilal apo[)l)ysis, the os femoris ; the 

 coronoides, the tihia; Sec. Tlic teetli, according to M. Spix, are nothing 

 else but nails, — an analopy niorc reasonable than that invoked by M. Oken : 

 the alveoli are what represent the phalanges, &c. &c. 



" In 1800, M. Antenrieth (in the Zootomical ylH««/.s of Wiedunian, vol. i. 

 paper 2, p. 47 et seq.) considered the operculum as resulting from the divi- 

 sion of the thyroid cartilage. 



In 1807, M. Geoffi-oy (in the 10th vohifiieof the Ann. du Mn.t.) supposed 

 that the opercula were the parietals detached from the cranium. 



In 1817, M. de niainvillc(//«//^/)H/V//A»H(.) endeavoured to establish that 

 the pre-opercidum is the os jiigale, and that the three oilier (lortions repre- 

 sent those «liich are generally found in the inferior maxilla of birds and 

 reptiles, over and above what are found in that of fishes. M. (ieoHroy o|)- 

 posed tothis, in 18lH(in his yV/i/avr);)//(V/fH«/()7/»V/»^), the jawof a lepisostens, 

 wiiich had been preserved b> me, and which is i|ijile as complicated as that 

 of any reptile, although the Icpiso^tens is l'^lrni^llcd with opercula as com- 

 ;5 L .' pictc 



