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).
Fig. 3. Deep Layer of the Inner Shoulder Muscles after Removal of the Humerus and its Musculature as well as the Collo-Scapularis Superficialis Muscles (cssp) and Thoraci-Scapularis Superficialis Muscles (thcsp).
Fig. 4. Shoulder Muscles after Removal of the Pars Scapularis of the Supra-Coraco-Scapularis (sps) and of the Biceps Muscle (b).
Fig. 5. Different View of Fig. 4.
Fig. 6. Shoulder Muscles after Removal of the Pars Coracoidea of the Supra-Coraco-Scapularis (spc) and Deltoides Scapularis Superior (dss) Muscles.