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Show 1890.] ANATOMY OF PODICA SENEGALENSIS. 429 differences between the condition of this muscle in the Rallidce that in the Colymbidos and Podicipedidce. The two latissimi dorsi muscles are shown as regards their insertion in the accompanying figure (Plate X X X I X . fig. 4 ) ; as is generally the case among birds, the posterior of the two muscles (which are hardly distinguishable in the middle of their course1) ends in a long thin tendon below the fleshy insertion of the other. It seems, from Prof. Fiirbringer's account [4] of the posterior latissimus dorsi, that its origin from the front border of the ilium is very inconspicuous among the Fulicaria.; indeed it was not observed at all in many cases. In the Colymbidce, on the other hand, this muscle has an extensive origin from the anterior border of the ilium ; Podica is in this particular Colymbine and not Ralline. The two rhomboidei have an extensively aponeurotic origin. This appears to be so far evidence in favour of the Colymbine affinities of the genus, since these muscles seem to have less tendon among the Rails ; this is certainly the case with Gallinula chloropus, which I dissected for the purposes of comparison along with Podica. The serratus posterior has a very large tendinous insertion on the end of the scapula ; in Gallinula chloropus this muscle is fleshy up to its insertion. The ambiens is present and has the usual relations. The semitendinosus is a powerful muscle ending in a muscular insertion covered by an aponeurosis. There is no accessory semitendinosus. The origin of the tensor fascice extends behind the acetabulum. The biceps is very large and important, with a somewhat unusual mode of insertion ; it is of course covered by the tensor fascia ; when that muscle is cut across and turned back the biceps is seen to arise from the whole of the postacetabular region of the ilium. It has no less than three insertions :-(1) By a broad flat muscular insertion on to the fascia covering the outside of the leg ; this strip of muscle springs from the outer side of the biceps just behind its division into the second and third insertions. (2) By a thickish long tendon which corresponds to the tendon of insertion in most birds; this passes in the ordinary way through a loop and is inserted some way down the leg. (3) The muscle divides just after the branch to the fascia of the leg into two branches, of which one has the insertion through the biceps loop that has just been described; the other branch forms a long thin muscle which becomes tendinous just before its insertion on to the leg some way below the second insertion. This singular modification of the biceps cruris (which is illustrated in Plate X X X I X . fig. 2) appears to be, so far as our present. knowledge enables us to speak, quite unique among birds ; it recalls in many respects the biceps in the Mammalia, though I have not the faintest desire to make any comparison with other groups : nothing seems to me to be more unreasonable than to compare muscles from one large group of animals to another; although I am 1 Their origins are closely side by side, and there is no space between, as there is, for example, iu Gallinula chloropus. |
