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Show 162 DR, P. CHALMERS MITCHELL ON THE [May 16, large tendon inserted to the radius (R.) and a very small tendon to the ulna (U.). There is also a second belly, smaller and rounder, arising almost wholly from the coracoid tendon of origin (BI. 2), and towards the lower end of the humerus passing into a round tendon which is inserted to the ulna only (U.), distal to the insertion of the ulnar branch of the tendinous fork of Biceps 1. This doubled condition of the biceps is practically repeated in Scolopax, except that Bi. 1 appears to supply only the tendon to the radius, and the same state of affairs is present in Gallinago, Charadrius, Himantopus, Vanellus, and Rhynchoia. It occurs also in Glareola and in Thinocorus, but in the latter the humeral head is degenerate although present. This complication of the biceps shows a link between the Charadriidse, through Chionis, with a more exaggerated peculiarity in some of the Gulls. The condition in Scolopax differs from that in Chionis practically only in the tendon of Bi. 1 in the latter being forked so as to be inserted both to the radius and ulna. If we suppose this fork in Chionis to be split up into the body of the muscle so as to separate the portion of the belly arising from the acrocoracoid tendon from the portion coming from the humerus, the Gull condition would be reached. In Laras, for instance, the tendon of origin arising from the acrocoracoid divides into two fleshy bellies, the one representing Bi. 2 in text-fig. and running to the ulna, the other, fused with Bi. 1 in the figure, running independently to the radius. As there is very strong evidence of other kinds for supposing that the Gulls are modified from a Charadriiform stock, it would seem natural to suppose that here we have to deal with a case of progressive complexity, starting from the Scolopax condition and leading through Chionis to the Gull condition. But it is important to remember that, in cases of muscles and tendons of birds, the general morphological course is from the more complex to the simpler, and, to my mind, it is more probable that the Scolopax and general Limicoline condition is a simplification from the Gull condition, Chionis showing how the simplification may have come about. Deltoidis patagialis.-This muscle is of moderate width in all these birds, and gives off the longus and brevis tendons from its relatively broad distal extremity, with not more than the slightest indication of division into peaks for the different tendons, and so far remaining in a primitive or archecentric condition. With regard to the tendons, (Edicnemus displays a condition markedly different from that found in all the others. The longus tendon is simple and slender ; it has an anchor to the humerus, and, after being joined by the biceps slip, gives off one or two very weak slips of fascia to the patagium, and then takes the usual course towards the wrist. The brevis tendon is simple, flat, and well marked ; it runs an undivided course towards the elbow, parallel with the biceps, and, close to its insertion, broadens out into a fan-shaped termination, which displays in a reduced condition the three slips named respectively a, ft, y by Fiirbringer. In all the |