OCR Text |
Show 252 MR. A. H. GARROD ON THE [May 5, IV. The presence or absence of the ambiens muscle in the genera of the Columbae. This muscle, of which the slender tendon runs in such a peculiar manner obliquely across the knee, arising from the supero-anterior margin of the acetabulum, and inserted into the muscular fibres of the flexor perforatus of the toes, is found in the greater number of the Pigeons I have examined, being present in about three fourths of the genera. The ambiens muscle is present in Caloenas, Carpophaga, Chalcopelia, Chalcophaps, Chamapelia, Columba, Didunculus, Ectopistes, Leptoptila, Leucosarcia, ambiens muscle is absent in Geopelia, Goura, Phlogoenas, Lopholamus, Macropygia, Metriopelia, Ocyphaps, Phaps, Pterocles, Turtur, Tympanistria, Zenaida, Zenaidura. Ptilonopus, Starncenas, Treron. The combination of the above-collected facts ought to be of considerable service in any attempts at classification; for, leaving the number of rectrices out of the question for the minute, of the eight possible variations of the three remaining characters, there are seven which are found to exist; in other words there are Pigeons k n o w n- (1) With an oil-gland, caeca, and an ambiens muscle, viz. Columba, Ectopistes, Macropygia, Pterocles, and Turtur. (2) With an oil-gland, no caeca, and an ambiens muscle, viz. Catenas, Carpophaga, Chalcopelia, Chalcophaps, Chamapelia, Leptoptila, Leucosarcia, Lopholamus, Metriopelia, Ocyphaps, Phaps, Tympanistria, Zenaida, and Zenaidura. (3) With no oil-gland, no caeca, and an ambiens muscle, viz. Didunculus. (4) With an oil-gland, caeca, and no ambiens muscle, viz. Phlogoenas. (5) With no oil-gland, caeca, and no ambiens muscle, viz. Star-nosnas. (6) With an oil-gland, no caeca, and no ambiens muscle, viz. Geopelia, Ptilonopus. (7) With no oil-gland, no caeca, and no ambiens muscle, viz. Treron, Goura. The only combination not found being that (8) in which, of the three structures concerned, the oil-gland only is wanting. The relative value of these different structural peculiarities is the point on which their value in classification evidently hinges. The number of rectrices being the most variable of them, its importance |