LIST OF ILLUSTRATIONS XXV 



FIG. PAGE 



400. Pectoral girdle of a Chelonian ..... 689 



401. Internal view of the plastron of the Greek tortoise . . 690 



402. Scales on ventral surface of plastron of Greek tortoise . 690 



403. Internal view of skeleton of tortoise .... 691 



404. Dissection of Chelonian heart — after Huxley . . .691 



405. Heart and associated vessels of tortoise — after Nuhn . 692 



406. Hyoid apparatus of a Chelonian .... 692 



407. Roof of the skull of a lizard (Varanid) . . . 695 



408. Side view of skull of Lacerta — after W. K. Parker . . 696 



409. Pectoral girdle of a lizard ..... 698 



410. Heart and associated vessels of a lizard — after Nuhn . . 699 



411. Lung of ChamcsleG vulgaris, showing air-sacs — after Wieders- 



heim ........ 700 



.}i2. Slow-woxia {Angiiis fragilis), alimhlesslizard . . . 702 



413. Anterior view of Python's vertebra .... 704 



414. Posterior view of Python's vertebra .... 704 



415. Snake's head — after Nuhn ..... 705 



416. Side view of skull of non-poisonous Pythonid snake . . 706 



417. Side view of skull of a poisonous snake .... 707 



418. Skull of grass-snake — from W. K. Parker . . . 708 



419. Lower siurface of skull of a young crocodile . . . 710 



420. First vertebra of crocodile . . . . .711 



421. First five cervical vertebrae of crocodile . . .712 



422. Cervical vertebra of crocodile . . . . .713 



423. Crocodile's skull : dorsal surface .... 714 



424. Pectoral girdle of crocodile . . . . .715 



425. Half of the pelvic girdle of a young crocodile . . 715 



426. Origin of amnion and allantois — after Balfour . .718 



427. Vertical section through backbone and ribs of a Chelonian 



and a Mammal — in part after Jaekel . . .721 



428. Position of organs in a bird — after Selenka . . . 727 



429. Anterior view of a dorsal vertebra of an ostrich . . 728 



430. Fore-limb and hind-limb compared . . . 729 



431. D iagrammatic section of young bird — after Gadow . . 730 



432. A falcon ........ 731 



433. Young heaxded grifhn (Gypaetus barbattis) — after Nitzsch . 732 



434 . Young feather and filoplume — after Nitzsch . . . 733 



435. Diagram showing a stage in the development of a feather . 733 



436. Types of feathers ...... 735 



437. Parts of a feather — after Nitzsch .... 736 



438. Entire skeleton of condor, showing the relative positions of 



the chief bones . . . . . . 738 



