| OCR Text |
Show 544 MR. F. E. BEDDARD ON THE [Apr. 21, reproduce one or two of the late M r . Forbes's sketches in illustration of the tensores of those birds, which have been but little described. The simplest form perhaps is to be seen in Synthlibo-rhavnphus antiquus. Here (fig. 3) there is but one tendon to the Fig. 3. ', Tensores patagii of Synthliborhamphus antiquus. a, slip to ulnar side of forearm. (From a M S . sketch by the late Mr. Forbes.) brevis muscle, which is inserted on to the forearm and passes over its muscles to be attached below to the ulna. This single tendon appears to correspond to the anterior of the two invariably present in Gulls and Limicoline birds : this is to be inferred from the fact that it gives off just the merest apology for the wristward branch found in those birds ; there is no patagial fan connecting this tendon wdtb tbe longus tendon ; but a thin tendon runs from the longus and is attached to the flexor side of the forearm. Fiirbringer's figure of these tendons in Alca torda shows no trace of this peculiar slip; but it seems to occur at least in the majority of the Alcidae. Its presence and the rudimentary character of the wristward branch of the main tendon of the brevis are the special peculiarities of the patagial tendons in the Alcidae. There are, however, as many as three separate tendons all running parallel in some species. In Lunda (see fig. 4), Ceratorhina (fig. 5), Brachy-rhamphus, and Una this is the case. In Fratercula and Alca there are only two. In a few species (in Fratercula for instance) where there is a patagial fan, a small ossicle as in the Petrels is developed. It seems clear, therefore, that the patagial muscles of the Alcidae do not on the whole favour the close relationship of the Alcidae to any other Limicoline birds, the resemblance to the Gulls |
