OCR Text |
Show 18 MB. F. E. BEDDARD ON THE [Jan. 6, itself and the neighbouring flexor ; its tendon runs at first beside and then above that of the extensor communis and is attached to the metatarsus as usual. (13) The Extensor communis digitorum arises from the crest of the tibia and for about two inches of inner half of outer face of the shaft. (14) Flexor hallucis longus.-This muscle arises from the femur by tendon, and from the fascia covering the flexor superficialis near to its origin. Its tendon is connected with that of the flexor profundus digitorum by a vinculum as in the majority of birds. The arrangement belongs to the first type described by Garrod [19], which characterizes Gallus and a large number of other birds ; the vin- Fig. 4. Connection between tendons of deep Flexors in Bhinochetus (a) and Scopus (b). culum is of some breadth, and it is attached to the tendon of the flexor communis before the bifurcation of the latter. I find that my description of this tendon in Scopus umbretta does not apply to every individual. I there [14] described1 a vinculum as being composed of two fibrous bands-one attached before the trifurcation of the tendon of the flexor profundus, the other attached to the branch of this tendon supplying the ivth digit. A dissection of a specimen which died in the Society's Gardens a day or two since shows that in both feet the vinculum is a single structure, which is attached to the branch of the tendon of the flexor profundus supplying digit iv., and not to the tendon before its trifurcation. In the strength of the vinculum Rhinochetus is unlike most of the Ardeidae, in which family there is a tendency for it to disappear. I have found this vinculum absent in a specimen of Nycticorax griseus; but in this case the vinculum was functionally replaced by a portion of one of the short flexor muscles, which, as in Rhea (cf. 1 A MS. note in the handwriting of Mr. Forbes with a sketch shows that my description of the two vincula in Scopus was probably correct. It is important to notice the variation. |