Roi/al Society. 227 



The author had examined it as preserved in rum by Capt Sawyer. 

 In several cliaracters tiiis animal strongly resembles the Ophidian 

 reptiles, especially in the formation of the jaws, which, with the ex- 

 ception of the apparent want of interarticular bones, are truly ser- 

 pentiform ; and from this resemblance, after showing the dissimi- 

 litude of the animal from the genera to which it is nearest allied, in 

 conjunction with the remarkable character aftbrded by the large 

 sac with which it is provided, Dr. Harwood assigns to it the generic 

 appellation of Ophiognathus, with the following generic character : 

 Corpus nudum, lubricum, colubriforme, comjjressrmi , sacco amplo 

 abdominali. 



Giving the specific name o^ ampuUaceus to this animal, the author 

 proceeds to describe it in detail. The specimen examined is about 

 four feet six inches in length, is very slender, and the tail has a fi- 

 lamentous termination occupying about 20 inches of the entire 

 length of the animal ; this begins at the termination of the dorsal 

 fin, which, like all the other fins, is small. The colour is a purplish 

 black, the filamentous portion of the tail being lighter than the rest. 

 The sac extends from near the extremity of the snout about twenty 

 inches down the body, and when partially inflated is about nine 

 inches in circumference : its greatest width, including the slender 

 body of the animal, is four inches. At the distance of a few inches 

 from its termination is the rectum, the course of which and of the 

 other digestive organs, owing to the tenuity of the sac, can readily 

 be traced. The author compares this appendage of the Ophiogna- 

 thus with similar organs in other animals of various classes, remark- 

 ing that the nearest approach to it among fishes is to be found in 

 the Diodons and Tetraodons, which possess a large abdominal sac, 

 on inflating which they become secure from the attacks of their 

 enemies, by the mechanical erection of the spines upon it. In the 

 present animal, however, its only use appears to be that of a float. 



The edges of the spiracula with which the Ophiognathus is pro- 

 vided, partially conceal three tufted branchiae on each side of the 

 head. It has a single row of teeth above and below ; no teeth on 

 the palatial bones, and is destitute of a tongue. The jaws are so 

 long, and their articulation of such a nature, that their opening is 

 wider then that of any other animal that the author is acquainted 

 with ; not excepting even the Rattlesnake. 



The entire form of this animal indicates that it must possess 

 great swiftness of motion in the waters. 



This paper is illustrated by three drawings of the Ophiognathus 

 and its several parts. 



Feb. 8. — A. Melville, Esq., and T. J. Pettigrew, Esq., were re- 

 spectively admitted Fellows of the Society; and a paper was read, 

 entitled " An Examination into the Structure of the Cells of the 

 Human Lungs, with a view to ascertain the office they perform in 

 Respiration; by Sir E. Home, Bart. V.P.R.S. Illustrated by mi- 

 croscopical observations, by F. Bauer, Esq. F.R.S." 



The author commences this paper by remarking, that the subject 

 of respiration has hitherto been regarded as belonging rather to 

 chemistry than to anatomy ; but that he finds reason to believe that 



2 G 2 process 



