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Show 300 MR. W. A. FORBES ON THE GREAT ANTEATER. [Mar. 7, eater, though present as rudiments in Tamandua, and well developed in Cycloturus1. In the larger specimen of the two examined by m e I find, however, a distinct one present on each side, lying in the muscles, about an inch long, nearly straight, of flattened form, with one end cylindrical. Similar ones were also present, closely attached to the sternum, but of smaller size, in the second specimen. Rapp (/. c. p. 40) found a rudimentary cartilaginous one in Myrmecophaga, though he (erroneously) denies one to Tamandua. There is also an accessory ossicle developed at the head of the fibula, as in some of the fossil forms. In the anterior cornu of the hyoid bone, I find in both specimens three distinct ossifications2. The proximal of these is a small nodule of bone, *3 inch long, articulating below with the basihyal * it is called the " apohyal" by Pouchet, but, according to the nomenclature now ordinarily employed, must really be the cerato-hyal3. The other two long curved ossifications of the anterior cornu must therefore be the epi- and stylo-hyals respectively. Both Rapp (I. c. p. 61) and Pouchet (* Me'moires,' p. 95, pl. xii. figs. 1-3) describe the posterior cornu as articulating externally with the anterior one. But in neither of m y specimens can I find any evidence of such a joint, as the two cornua, when in their undisturbed condition, are separated by a considerable space, in part occupied by a muscle (the inter cornu alis, Owen, /. c p. 127); and in the cleaned bones I also find it impossible, without violence, to bring the two arches into such contact together. In Tamandua, though there is a distinct ligament between the two arches, they are nevertheless similarly separated ; and neither Duvernoy4, who dissected this species, nor Owen, in his account of Myrmecophaga, allude to any such interarticulation existing ; Owen's figure (pl. xxxix. fig. 2) indeed clearly shows the two cornua separated by the inter-cornualis muscle, as also observed by me (cf. Plate X V . fig. 1, int). At the place where the three main ducts of the submaxillary glands of each side converge to become intimately connected together by their walls, though they still remain quite separate tubes, they are covered by a mass of muscle which forms a bulb-like swelling for an extent of If inch on the inferior aspect of the conjoined ducts (Plate XV. fig. 1). It is this mass of muscles that has been described by Owen (I.e. p. 126) as the " constrictor salivaris," a name adopted by Pouchet subsequently. The external aspect of the ducts is also, for the posterior half inch of this space, covered by a thick muscular coating, so that in this portion the three ducts are encircled by a broad ring of muscular fibres. These fibres arise from the anterior edge of the anterior hyoid cornu, on each side of the junction of the stylo- and epihyal 1 'Osteology of the Mammalia,' by W . H. Flower, p. 235: London, 1876. 2 The accounts given by different authors of the compositon of the hyoid bones in the Anteaters differ considerably inter se. Cf. Pouchet, 'Memoires ' pp. 93-95. 3 In Tamandua I am unable to find any corresponding opsification, though both the epi- and stylo-hyals are well developed. 4 Mem. Soc. Hist. Nat. Strasbourg, 1830; and Cuvier's Anat. Comp. 2me <§d. iv. part 1, p. 476. |
