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Show 1901.] ON THE LINGUAL MYOLOGY OF PARROTS. 277 showed an extensive inflammatory tumour on the right side, connected by a pedicle to the inner surface of the skull, perforating the bone by a circular opening, and causing thickening and breaking up of the horn-support. Mr. Holding also exhibited the skull and horns of another Japanese Deer, showing a curious spur growing from the pedicle of the right horn, an uncommon position for a supernumerary horn ; such horns, when they do occur, usually having their origin below the pedicle or above the burr. Mr. G. P. Mudge gave an account of his researches on the Lingual Myology of Parrots, with a Classification of the Order based upon the structure of the Tongue. The ceratoglossus inferior exhibited structural modifications which could be grouped in nine stages, arranged in a graded series. In its most primitive form it consisted only of an anterior portion related to the basihyal ; and in its most specialized condition of an additional posterior portion related to the hypobrancbial, and connected with the anterior part by a strongly developed tendon. The primitive. muscle possessed no tendon but a tendinous fascia. All stages in the development from the primitive to the specialized condition could be traced, in the form of a gradual posterior extension of the anterior primitive muscle along the hypobrancbial and in the gradual thickening of a localized, elongated tract of the tendinous fascia, with its concurrent posterior extension along the developing posterior portion of the muscle. Iu Brotogerys and Ptistes the left-arid right-hand muscles were not alike, and it was showm that the exceptional left-hand muscle of the latter Parrot could be directly derived from that of Cacatua leadbeateri by the completion of the incipient retrogression there indicated. In virtue of the structural features of this muscle, Cacatua, Stringops, Ara, Ccdopsittacus, and Ccdyptorhynclius were primitive, and the Lories were specialized; but some species of Cacatua and Ara were more advanced than others of the same genera. The thyroglossus had arisen from the thyrohyoideus in three ways, each of which evolved along its own line through two stages : at the third stage all three ways converged, whence the further evolution of tbe muscle could be traced through three higher stages. The insertion and origin of the muscle in the highest stage was similar to that of its most primitive condition ; but it was shown that there were reasons for regarding this apparently primitive condition as resulting from a secondary return to the original one. The thyrohyoideus was shown to be much more extensive in its primitive condition than was now represented in the majority of Parrots. In respect of this, Cacatua, Stringops, Calopsittacus, Calyptorhynchus, Microglossus, Eclectus, and Nestor were primitive, since they possessed in the form of a thyrohyoideus accessorius evidence of the once more extensive nature of the muscle. In Stringops the anterior mylohyoideus extended back to the PROC. ZOOL. Soc-1901, VOL. I. No. XIX. 19 |