20 A N A T M V A X D I' II Y S I L Od V O F 



CHAPTER II. 



Tin- preceding chapter has been altogether taken up with anatomical descriptions 

 of the respiratory organs and (heir appendages. So much that was new was 

 met with during OUT dissections, that it was thought better to separate the 

 description of the anatomy from the physiological statements. We have thus the 

 physiology of the respiratory organs still to describe, and this can now lie done 

 without repeating any more of the anatomical detail than is necessary to enable 

 the reader to comprehend the actions of the organs concerned. 



The history of the theories entertained as to the nature of the respiratory 

 motions in turtles, appears to us one of the most extraordinary iu the records of 

 science. Totally misunderstood by the earlier naturalists and biologists, or con- 

 founded as to type with the respiration of Batrachians, this function in turtles was 

 first rightly comprehended, at least to some extent, by 11. Townson in the latter part 

 of the last century. How far he went, and how far he was correct, we shall more 

 fully point out in another place. The authority of more eminent naturalists, and 

 an obstinate disposition to associate tin; turtle with the frog, and to insist on 

 similarity as to the execution of their functions, gradually drew attention from 

 Townson's statement, and more modern authors have paid it no deference' what- 

 ever; yet, as we shall distinctly show, all the later writers are utterly wrong, and 

 his opinions as to the facts in question are thus far the only ones which seem to be 

 correct. In reading his very ingenious essay, which we have elsewhere quoted at 

 length, p. 2, it is hard to see how the statements and evidence could have failed of 

 more respectful and permanent attention. A complete review of the theories enter- 

 tained in regard to the respiratory function in Chelonian reptiles, will more fully 

 illustrate the above remarks. 



\s early as 1719, Malpighi 1 described the respiration of turtles as similar to 

 that of frogs. Both alike wore supposed to distend the lungs by swallowing air, 

 so that, in place of air being drawn into the lung-sacs, it was forced into them by 

 the movements of parts above the trachea; but while in the frog this was effected 

 plainly through the aid of the bellows-like mouth, in tin 1 turtles their vast hyoid 

 apparatus was by some supposed to constitute a forcing pump of similar purpose and 

 nature. The authors of Malpighi's era shared these opinions, and with the one notable 

 exception above mentioned, they have stood almost uncontradicted up to the date 

 of a paper by one of the authors of the present essay. 



1 Adversaria Anatomiea, i \ Aniraadv, 29, 



