_Interosseus Cruris_ (Kniekehlmuskel). A small muscle stretching between the distal ends of the fibula and tibia with almost transverse fibers; it is covered dorsally by the tibio-fibulare ligament and appears as a distal division of the tibialis posticus muscle. _Flexor Digitorum Brevis_ (Flexor longus accessorius, Flexor brevis perforatus). Springs from the bones of the foot and from the strong tendon of the flexor digitorum longus muscle. It divides into three bellies for the second, third and fourth toes. The first two are pierced by the above-mentioned tendon of the flexor digitorum longus and are inserted on the next to last phalanx of the second and third toes; the third, on the contrary, is inserted on the claw joint of the fourth toe and is not perforated; there is no tendon to the fourth toe from the flexor digitorum longus muscle. _Extensor Hallucis Proprius_ (Plate V., Fig. 3) (Kurzer gemeinschaftlicher Zehenstrecker, Extensor hallucis). This muscle springs by a short, flat, fairly strong tendon from the outer dorsal border of the distal half of the fibula. It is inserted: (1) on the proximal half of the first metatarsal bone, (2) a second much weaker part is united with the tendon of insertion of the tibialis anticus extensor longus digitorum to the first metatarsal bone. THE TAIL MUSCLES The muscles of the tail have, as shown by Gadow, the character of the primitive body muscles, with their primitive metameric division, fairly plainly preserved. This musculature is arranged in four rows of trumpet-shaped cones, one projecting into the other, by which arrangement each metamere exhibits a transverse zigzag line of four anteriorly and three posteriorly directed points. _Ilio-ischio-caudalis_ (Plate III., Figs. 1 and 2, is. cd., Plate IV., Figs. 1 and 2, is. cd.) (Ischio-coccygeus). The crocodile is the nearest to the typical condition in the musculature of the tail. The lateral and ventral part of the tail musculature forms a broad mass that extends to the end of the tail; it lies immediately under the skin and springs from the caudal ribs (transverse processes--Gadow) and from the spinous processes of all the caudal vertebræ. The entire side musculature of the tail ends cephalad in several portions; the most ventral and medial of these bound the cloaca as an at least slightly developed, morphological sphincter; the lateral portion is attached to the posteroventral border of the ischium; while the dorsal portion is inserted by two heads on the first caudal rib and on the posterior spine of the ilium. PLATE I. SHOULDER MUSCLES OF CROCODILUS ACUTUS. (From Bronn after Fürbringer.) FIG. 1. SHOULDER MUSCLES AFTER REMOVAL OF THE SPHINCTER COLLI MUSCLE (_sphr_). FIG. 2. SHOULDER MUSCLES AFTER REMOVAL OF THE SPHINCTER COLLI MUSCLE (_sphc_).