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Show 1870.] MR. HUDSON ON THE BIRDS OF BUENOS AYRES. 545 chechus rosmarus). After a preliminary notice of the labours of Daubenton, Home, Von Baer, and others, he proceeded to treat on the outward characteristics of the young male Trichechus which the Society possessed in 1867. Dwelling respectively on the colour, general configuration, manner of walking, skin-folds, and head, he closed this section by a careful study of its pectoral and pelvic limbs as compared with those of Phoca. With a few remarks on viscera and genital organs, he more fully described the vascular channels aud the vocal organs, verifying Von Baer's observation as to the diminutive size of the epiglottis. Of the myology nothing heretofore has been known save Sir Everard Home's incidental notice of the Walrus possessing well-developed interossei. Dr. Murie having dissected somewhat minutely the fleshy structures, proceeded to point out that though the genera Trichechus, Otaria, and Phoca manifest considerable variety in form, gait, and degree of limb-movement, they, nevertheless, muscularly present general agreement. In the presence of a coraco-brachialis, a flexor brevis manus, a pronator quadratus, an opponens poliicis, and a palmaris brevis, the Walrus is differentiated from the Eared and Earless Seals. Though deficient in concha, the auricular muscles are remarkably large. There is an external anconeus as in Otaria; and, as in it and Phoca, there are a double set of extensors of the manus. Compared with Seals, there are two extra peronei and a flexor brevis hallucis. This paper will be published in full in the Society's ' Transactions.' The following (5th and 6th) letters on the ornithology of Buenos Ayres*, addressed to the Secretary by Mr. W . H. Hudson, C.M.Z.S., were read :- (No. V.) " Buenos Ayres, March 22,1870. " M Y D E A R SIR,-In a letter, dated a few days back, I gave you some account of the Teenioptera variegata. This bird, a Plover in habits and a Thrush in appearance, finds a congenial habitat in this part of the country when the cold compels it to forsake the barren plains of Patagonia. Before winter sets in, the giant thistles that cover the plains in summer dry up and crumble to dust, and, the grass being eaten down very close by the innumerable flocks of sheep, the earth presents all the smoothness so agreeable and so necessary to this species. " Even at night they do not seek for shelter, as do the Trupials, Anthi, and other passerine birds that roost on the ground, but, Plover-like, remain on the bare level places they frequent. I do not recollect ever having met them on the grassy pampas west of the Buenos-Ayres frontier. As they do not perch on reeds, they would naturally avoid such places, preferring the inhabited districts. Thus the settlement of the country has been favourable to this species, as it has to the Biscacba, the Burrowing-owl, and the Teru-te'ru. * For Mr. Hudson's last letter, see P. Z. S. 1870, p. 332. |