276 FISHES. 



palatine, pterygoid, and tympanal system, which has its separate 

 motion*. 



* The history of researches on the bones of the head in fishes is entirely recent, 

 and can be traced scarcely to twenty years back. Gouan, in his History of Fishes, 

 in 1770, and Vicq. D'Azyr, in his Memoirs on their Anatomy (Memoires des Sav. 

 Etrang. vol. VII,) mention nothing respecting the bones of the head, except what is 

 very vague, and occasionally erroneous. There were no more than a few insignificant 

 words on the composition of the cranium in this class, in my Lectures on Comparative 

 Anatomy up to 1798. What was said there gave very little details of the bones of 

 the face ; and it was also very imperfect, for the sphenoid was compared to the 

 vomer, the maxillary bone to the zygoma, &c. 



In fact, at that period our collections were destitute of almost every sort of aid 

 towards the osteology of this class, and it was this circumstance that led me to 

 devote myself uninterruptedly to the task of filling up this great gap. The innumerable 

 specimens which I have collected, and the use of which I never denied to any one, 

 formed at the same time the groundwork for the laborious undertaking which I am 

 now presenting to the public, and for the memoirs of several naturalists, who there- 

 fore might easily appear to have anticipated me ; and, if they had anticipated me on 

 on some particular points, still I am far from complaining of publications and 

 researches made with my consent, and which have been of use to me. The only 

 thing I was anxious about was that those whom I allowed to take the benefit of the 

 materials which I had collected for the purpose of filling up the gaps in my first work, 

 would have abstained from selecting that early performance for their criticisms, thus 

 leaving it to be inferred that I was stationary at this point of my researches. 



About the year 1807, M. GeoflFroy, in addition to his Memoir on the Osteology of 

 the Head of the Crocodile, inserted in vol. X. of the Annales du Museum, published 

 some essays to determine the bones of the head in the tortoise and some fishes ; and 

 it was at that time that he entertained the idea of the operculum being a parietal 

 bone, and emanating from the cranium. This theory was published by him in his 

 Memoir on the Bones and Head of Birds, which was printed in the same volume, 

 X, p. 342. 



I was led myself also to examine the head of the crocodile, and gave, in the 

 Annals of 1808, my osteology of living crocodiles and other reptiles. But since 

 that period I have been devoted to my large Treatise on Comparative Anatomy, and 

 particularly on that branch connected with the osteology of the head ; and in 1811 

 I delivered my settled theory on its complete state in my Lectures. An abridged 

 summary of it was given by me in a note on the osseous pieces of which the head of 

 vertebrated animals consisted. (Annales du Museum, vol. XIX, p. 123 — 128). 



I described in great detail the bones of the face of fishes in my Memoir on the 

 Structure of the Upper Maxillary Bone. This was read at the Institute in March, 

 1814, and was published in vol. I. of the Memoirs of the Museum. In the same 

 volume, pi. 16, I supplied some examples of the varieties of the configuration of 

 these bones, which were taken from the coryphena, labnts julis, and the razor-fish. 

 Lastly, in 1817,1 published, in my " Regne Animal," three plates of the head of the 

 cod, in which the whole of the bones have their names respectively. 



In 1817 M. Blainville published, in the Philomathic Bulletin, a Memoir on the 

 Operculum of Fishes, in which he asserted that the preoperculum was the jugal bone, 

 and that the three other pieces were representatives of those which were found extra 

 in the lower jaw of the reptiles and birds, as compared with that of the fishes. The 

 author aflSrms that he communicated these ideas long before, and he gives them the 

 date of 1812. But they were instantly refuted by M. GeofFroy, to whom I showed, 

 amongst my preparations, the jaws of a lepisosteus, quite as complicated as that of 

 any reptile, yet this fish actually had opercula as perfect as those of any fish. 



In 1818 M. GeofFroy, in his Philosophic Anatomique, announced this fact, and at 

 the same time suggested the notion that the bones of the operculum corresponded 

 with the four little bones of the ear, that is to say, the operculum with the stapes, 

 the sub-operculum with the incus, the interoperculum with the malleus, and a fourth, 

 which is often merely a vestige, to the lenticular (in this country, the orbicular) bones, 

 whilst the preoperculum would be the frame of the tympanum. 



