THE FROG. 18 



PLATE IV. 



THE FKOG. THE SKELETON. THE MUSCLES OF THE HIND-LIMB. 



J I IG . I. The entire axial skeleton, with the limb-girdles and the limbs of the right 



side, drawn from above with the body in the resting attitude.* 



Macerated preparation, x 1|. The humerus and the metacarpal of the second digit 

 in the manus, drawn separately, are those of the male. 



FIG. II. The first vertebra, seen from the front. 



FIG. III. The fourth vertebra, seen from the same aspect. 



FIG. IV. The fifth and sixth vertebrae, from the side, in the natural position. 



FIG. V. The ninth (sacral) vertebra, seen from behind. 



The articulations of the centra are shown in section in Fig. XIII., Plate I. 



FIG. VI. The shoulder-girdle, seen from the front, the left scapula having been 

 straightened out. 



FIG. VII. The left half of the hip-girdle, from the side.f 



(Figs. II. to VII., all x li.) 



FIG. VIII. The skull (cranio-facial apparatus), after removal of the membrane bones 

 of the right side, seen from above. 



The mandible and hyoid are excluded. Wet preparation.^ 



FIG. IX. The same, seen from beneath. 



In both this and the above, the membrane bones removed are drawn independently ; 

 in this figure, however, one half of the parasphenoid is indicated in situ. 



FIG. X. The same, seen from the side, with both mandible and hyoid in place. 

 FIG. XI. Back view of Fig. VIII. 



FIG. XII. Sectional view of the above, exclusive of the hyoid. Meckel's cartilage has 

 been exposed. 



(Figs. VIII. to XII., all x 2.) 



FIG. XIII. The body of the hyoid, of a young frog, x 2. 



(In all the above figures the cartilaginous parts are stippled.) 



" The so-called calcar, c., is generally composed of two or more pieces, and represents the remnant of a sixth digit. 

 Compare Born, " Die sechste Zehe der Anuren," Morjth. Jahrk., vol. i., 1875 ; Wiedersheim, " Lehrbuch der vergleichenden 

 Anatomie," Jena, 1883. See also Marsh, " The Limbs of Sauranodon," American Journal of Science and Arts, 

 vol. six., 1880. 



t The upper cartilaginous articular-end of the ilium may be appropriately termed the supra-ilium. 



1 See Appendix F. 



