_Ischio-femoralis_ (Plate III., Fig. 1, is. f.) (Adductores, Adductor longus, Adductor primus). Springs directly (without tendon) from the entire anterior border of the ischium. It is band-like and, running over the tendon of the pubo-femoralis internus and externus muscle, is inserted as a broad, fleshy tendon on the middle third of the inner, posterior surface of the femur. _Pubi-ischio-femoralis Externus_ (Plate III., Fig. 1, p. is. f. int., Plate IV., Fig. 1, p. is. f. int.) (as a whole: Quatuor pectinei [partim]; in parts: I. Marsupialis externus, Obturator externus; II. Quadratus femoris). This muscle arises in two parts. The anterior part is broad and comes from the entire ventral and inwardly turned outer surface of the pubis. Its insertion is on the femur in conjunction with the first part of the pubi-ischio-femoralis internus. The second part is shorter but thicker than the first and springs from almost all of the outer surface of the ischium that is not covered by the origins of the ischio-femoralis, pubi-ischio-tibialis, and flexor tibialis internus muscles. It is inserted, by a strong, short tendon, on the trochanter, somewhat caudad to the insertion of the pubi-ischio-femoralis internus. _Pubi-ischio-femoralis Internus_ (Plate III., Fig. 1, p. is. f. int., Plate IV., Figs. 1 and 2, p. is. f. int.) (as a whole: Iliacus internus + Quatuor pectinei [partim]; in parts: I. and II.: Kamm-Muskeln, Pectineus inferior [I.] + superior [II.], Marsupialis internus, Obturator internus; III., Iliacus [Darmbeinmuskel], Iliacus internus). This muscle arises by two or three parts: I. The anterior arises, without tendon, from the greater part of the inner and anteriorly directed surface of the pubis; median to this, in the alligator, is a small bundle, II., which unites with part I. These unite with the pubi-ischio-femoralis externus to form a strong tendon that is inserted on the trochanter. III. This is a larger muscle that springs without tendon from the inner surface of the body and transverse processes of the twenty-fifth and twenty-sixth (in alligator) vertebræ, from the part of the ilium that lies between these transverse processes and the ischium, and from a small part of the ischium. It is inserted on the whole inner surface of the proximal third of the femur. _Pubi-ischio-femoralis Posterior_ (Plate III., Fig. 1, p. is. f. post., Plate IV., Figs. 1 and 4, p. is. f. post. and pb. is. f. m. post.) (Adductus [partim], Gemellus, Obturator internus). Springs without tendon from the whole caudally directed border of the ischium. It is inserted, by a short tendon, near and laterad to the tendon of the ischio-femoralis muscle, on the hinder surface of the upper leg.