_amb_, ambiens; _cap_, _ext_, _gastr_, external head of gastrocnemius; _cap_, _int_, _gastr_, internal head of gastrocnemius; _cd_, _fm_, caudali-femoralis; _cd_, _il_, _fem_, caudi-ilio-femoralis; ex. il. tb. extensor ilio-tibialis; _ext_, _l_ (_long_), _dig_, extensor longus digitorum; _fl_, _tb_, _ext_, flexor tibialis externus; _fl_, _tb_, _int_, flexor tibialis internus; _fm_, _tb_, femoro-tibialis; _il_, _cd_, ilio-caudalis; _il_, _cost_, ilio-costalis; _il_, _fib_, ilio-fibularis; _il_, fm (_il_, f), ilio-femoralis; _il_, _s_, _cd_, ilio-sacro-caudalis; _is_, _cd_, ischio-caudalis; _is_, _f_, ischio-femoralis; _ob_, _ext_, obliquus externus; _pb_, _cd_, pubi-caudalis; _pb_, _is_, _tb_, pubi-ischio-tibialis; _pb_, _tb_, pubi-tibialis; _peron_, _ant_, peroneus anterior; _peron_, _post_, peroneus posterior; _p_, _is_, _f_, _ext_, pubi-ischio-femoralis externus; _p_, _is_, _f_, _int_, pubi-ischio-femoralis internus; _p_, _is_, _f_, _post_, pubi-ischio-femoralis posterior; _qudr_, _lb_, quadratus lumborum; _rect_, rectus abdominis; _tib_, _ant_, tibialis anticus; _tib_, _post_, tibialis posticus; _trans_, transversus abdominis; _tr_, _per_, transversus perinei; _m_, _post_, _il_, posterior border of ilium; _ob_, foramen in pubis for the obturator nerve; _o_, _il_, ilium; _o_, _is_, ischium; _o_, _pb_, pubis; _o_, _cl_, cloacal bone; _pr_, _l_, _pb_, lateral process of pubis; _pr_, _tr_, transverse process; _sp_, _ant_, _il_, anterior spine of ilium; _Sy_, _p_, symphysis pubis; _Sy_, _is_, symphysis of ischium; _tb_, _is_, tubercle of ischium. [Illustration] PLATE IV. (From Bronn, after Gadow.) FIG. 1. ALLIGATOR MISSISSIPPIENSIS. INNER SURFACE OF THE PELVIC REGION, LEFT SIDE. THE PUBIS, ISCHIUM, AND VERTEBRÆ ARE CUT THROUGH THE MEDIAN PLANE, XXVIII, 28th VERTEBRA. FIG. 2. HATTERIA PUNCTATA. FIG. 3. A. MISSISSIPPIENSIS. THE DEEPEST MUSCLES ON THE PLANTAR SURFACE OF THE LEFT HIND FOOT. ROMAN NUMERALS IX-XII, SHORT TOE MUSCLES. FIG. 4. A. MISSISSIPPIENSIS. LEFT LEG FROM THE POSTERO-MESIAL ASPECT. THE PLANTAR FLEXOR MUSCULATURE IN SITU, AFTER REMOVAL OF THE GASTROCNEMIUS MUSCLE AND THE ASSOCIATED MUSCLES. ROMAN NUMERALS, VI-X, SHORT TOE MUSCLES.