| OCR Text |
Show 470 DR. R. W. SHUFELDT ON [Nov. 16, On the Mode of Insertion of the Patagial Muscles of the Pectoral Limb. Having considerable faith in the value in classification of the arrangement of the insertional extremities of the tendon of the tensor patagii brevis muscle, and the forms of the patagial muscles generally, as single characters, it was with no little interest that I carefully removed with m y scalpel the integuments over this region, for the first time in my experience in Geococcyx. The late Mr. Garrod's excellent work in this direction is now familiar to all ornithologists; but on this occasion I refrained from consulting any of the accurate drawings he has left us illustrating these parts in many groups of birds until I had actually completed my dissection, and m y drawing of it, which is shown in Plate XLIII. fig. 2. I then opened his " Collected Scientific Papers " and proceeded to compare my figure with his numerous illustrations of the same dissection among other birds. Being familiar with the arrangement of this tendon in a great many North-American birds from my own labours, I was confident that the condition of things in Geococcyx californianus was a marked departure from anything I had previously met; nor did I expect to find anything in Garrod's illustrations that would prove to be exactly like it. But in this last hope I was very agreeably disappointed, for I find that it corresponds almost exactly with the state of affairs found by this talented anatomist to be present in certain Galbulidae. To satisfy one's self of this fact it is but necessary to compare my figure with the Jacamar dissected by Mr. Garrod, as shown in his work (plate 23. fig. 1, tendon of tensor patagii brevis in Urogalba paradisea), and the striking resemblance will be at once appreciated. He has simply cleared his tendon more completely of its investing fascia than I have, and still further separated its several slips; while in my figure of Geococcyx the tendon is shown as it presents itself immediately after turning back the integuments, or, in other words, exactly in situ. The liberty taken by Mr. Garrod to still further show these slips and their exact insertions is perfectly permissible, and often resorted to for the purpose laamed. It will be seen that after the tendon of the tensor patagii brevis arrives over the proximal third of the belly of the extensor metacarpi radialis longior muscle in Geococcyx it trifurcates, one slip passing downwards to become inserted immediately below and on the outer aspect of the extensor carpi ulnaris muscle; the shortest slip at once attaches itself to the extensor metacarpi radialis longior, while the longest division of all passes with the last-named muscle to become inserted with it upon the outer condyle of the humerus. As for the muscular portion of these patagial muscles above in this Ground-Cuckoo, I have represented them with the arm turned somewhat differently than the position Mr. Garrod was wont to give it. It will be seen, however, that the bulk of this muscular portion in Geococcyx, as in Urogalba, belongs to the tensor patagii brevis muscle. |
