| OCR Text |
Show 200 DR. T. S. COBBOLD ON ENTOZOA. [Feb. 1, avian stock as an independent offshoot at much the same time as did most of the other important families. It m a y be fairly asked what reason there is for the assumption that there was a sudden break up of the bird-type at any particular period. It appears to m e from the study of anatomy that this was the case ; and it is evident that the acquisition of wings by the previously terrestrial type form must have suddenly interpolated a large number of intruders into domains already occupied, and must have all at once called forth a new aerial struggle for existence, which, from the generalness of its action must, within a short time, have brought out a great number of special characters by natural selection. EXPLANATION OF THE PLATES. PLATE XII. Fig. 1. Proventriculus and gizzard of Chauna derbiana, cut open, and part of the front wall removed. 2. Anterior view of lower portion of windpipe of C. derbiana. 3. Back view of same, the muscles of the left side having been removed. 4. Bight side view of. same. 5. Portion of right coracoid bone (c) with coraco-brachialis longus (cib.l) • and coraco-brachialis brevis (c.b.b.) in situ, of Crax globicera. The expansor secundariorum (e.s) is seen to spring partly from the first-named muscle. P L A T E XIII. Fig. 1. Caeca of Chauna derbiana, with the anterior wall partly removed to show the cavity intervening between the small and large intestine into which the caeca open. 2t The caeca, external view. PLATE XIV. Fig. 1. Axillary muscles of right side of Chauna derbiana. e.s, expansor secundariorum; pl, great pectoral; p2, second pectoral; c.b.l, coraco-brachialis longus; b, biceps; t, triceps; t.p.b, tensor patagii brevis; sc, scapula; st, sternum; c, coracoid; / furcula; h, humerus; c.v, cervical vertebras; tr, trachea: S.B, secondary remiges. 2. The same part, left side, of Gallinula chloropus. B. slip, biceps slip; t.p.l, tensor patagii longus. PLATE XV. Fig. 1. Muscles of right side of interior of pelvis and inner side of thigh of Chauna derbiana, the muscles of the anterior abdominal wall having been removed. o.i, obturator internus; Amb, Ambiens; Quad, Quadriceps extensor; Ad, adductor; s.t, semitendinosus. 2- The same parts of Euplocamus albocristatus, similarly lettered, sart, gartorius. 4. Notes on Entozoa. Part III. By T. SPENCER COBBOLD, M.D., F.R.S., F.L.S., Correspondent of the Academy of Sciences of Philadelphia. [Received January 18, 1876.] (Plate XVI.) In continuing the "Notes" commenced in 1873, I may observe that I have recently received important additions from naturalists |
