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Show 476 DR. J. MURIE ON THE GULAR POUCH OF OTIS. [June 25, seeds, grass, or leaves being found in it appears to me only an accidental circumstance, the absence of great muscularity in the walls permitting the foreign body temporarily to lie there. In this respect I also agree with Naumann* and Yarrellf, although I hardly think that the latter naturalist was right in stating " such foreign substances would destroy the bird by inflammation." 3. What Cullen and other earlier authors (Schneider and Deg-landj, for example) have said regarding the presence of the gular pouch during the breeding-season in Otis tarda, and what has been observed in the Australian Bustard in our Gardens, show that the pouch is a feature connected with the reproductive function, and only a temporary air-chamber. The gaudy Peacock swells out with tremulous emotion; the Turkey Cock, the Tragopan, and other birds erect their wattles; the Pouter Pigeon no less shows sexual phenomena akin, though in some respects differing from that of the Bustards. 4. From the statements of various observers, then, it would thus appear that at least five species of Bustard occasionally possess a gular pouch, namely Otis tarda, O. kori, O. australis, O. nigriceps, and O. tetrax; but others yet unexamined may also have it; so probably it obtains in the family Otidce. 5. In a moderate-aged male Burchell's Bustard, as we have seen, the pouch is very limited in dimensions. In young birds of this and other species it has never been found; and where its existence has distinctly been proved, it invariably (with one apocryphal exception) has occurred in fully grown males. From these data I think it may be inferred that the said "gular pouch" is an organ of adult growth possessed alone by the male, and not attaining its full dimensions until the bird has arrived at maturity. To such circumstances the incidental non-development of the organ may be ascribed. 6. There still remains the unexplained peculiarity that some adult, and possibly it may be old, males have it not. This I confess is not at all clear to me. If the organ is reciprocal with the procreative faculty, enlarged or subject to an accession of growth during the instinctive sexual season, then I cannot conceive why traces of the pouch, and especially its opening, do not at all times exist-that is, as soon as the bird has arrived at maturity. That the sac is not the result of a bursting and expansion of the cellular tissue of the throat, as Mr. Bartlett has suggested, I am perfectly satisfied of. In emphysematous disease of the lungs in the higher Mammalia rupture of the pulmonary cells and enlargement into a sacculus does peradveuture take place; but in the cellular tissue of the neck of birds we have tissues differently constructed. Moreover the same objection applies in either instance; for in the lung, as would be in the Bustard's neck, such a lesion could not be inflated and com- * Op. cit., and Ibis, 1862, p. 115. t L. c. p. 118. \ See Newton's paper, I. c. pp. 107, 115, quotations being there given from the authors; the original volumes it lias not been m y fortune to consult. |