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6 inches. Its enlarged and extremely elastic pharynx commence* 

 with the enormous sac, or air-vessel, which extends about 20 inches 

 from the snout. It is so delicate that it could not be fully inflated, 

 but when partially so, measured about 9 inches in circumference, be- 

 low its union with the tail, and its greater diameter, including the 

 slender body of the animal, 4 inches. 



At about an inch from its termination it is perforated by the rec- 

 tum, and its tenuity rendered that and the other intestines easily 

 traced. They appear to be sustained beneath the very imperfect 

 ribs by a membranous expansion, not being affected in position by 

 inflation of the sac. 



The skin all over the body is particularly soft and shining. The 

 spiracula are large, irregularly oval, and unprovided with external 

 rays, and their edges partially conceal on each side three tufted 

 branchiae, at about 5 inches from the snout. The fins are all very 

 small. In the pectoral ones is a peculiarity not found in other ap- 

 odal genera, being chiefly composed of an adipose disc, which is ter- 

 minated and nearly surrounded by a narrow radiated membrane, in- 

 stead of the latter originating from the body immediately. The tail, 

 after the termination of the dorsal fin, becomes a slender tape-like 

 filament, nearly 20 inches longer ; and above this point some minute 

 filaments take their growth from it. The anal fin commences where 

 the sac terminates, and ends 14 inches from the end of the tail. 



The most curious parts of the animal are, however, the head and 

 jaws. It has no tongue ; the teeth are disposed in a single row 

 above and below. The ossa palati are destitute of teeth, and the 

 jaw-bones are so long, and their articulation so loose, as to be sus- 

 ceptible of distention beyond any other animal, not excepting the 

 rattle-snake ; and when fully distended they describe a large circle, 

 and appear but the opening of an ample sac. 



The author illustrates his description by three figures, and con- 

 cludes by observing that the Ophiognathus is one of the most vora- 

 cious of the inhabitants of the ocean. Its entire form would indicate 

 great swiftness of motion, performed doubtless by the same sinuous 

 inflections in water, which excite our admiration in serpents on land. 

 In what manner its pouch is employed in its economy he does not at- 

 tempt to determine, nor to decide whether it be capable of secreting 

 the contained air, or whether water be allowed to enter it. 



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 Everard Home, Bart. V.P.R.S. Illustrated by Micro- 

 scopical Drawings from the Pencil of F. Bauer, Esq. F.R.S. Read 

 February 8, 1827. [Phil. Trans. 1827,^.58.] 



The author commences this paper by remarking that the subject 

 of respiration has been hitherto regarded as belonging rather to 

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

 process to be more simple than is imagined, and more within the 



