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Show 834 MR. P. E. BEDDARD ON THE [Dec. 3, which show a number of divergences other than those indicated by Mayer. Muscles of the Head, Trunk, and Fore-limb. The obliquus externus was, as Meckel has pointed out, overlooked by Mayer, who, however, curiously enough, figures it. It is only found in the posterior region of the abdomen, where it covers the pectoral and arises from the symphysis pubis and also from the rhomboidal area, mentioned in connection with the abdominal portion of the pectoral. The Rectus abdominis is in three portions; one arises from nearly the entire length of the femur, and has been confounded by Mayer with the abdominal portion of the pectoral. As a matter of fact, it ends in a transverse band of tendon (a tendinous inscription), from which the pectoral arises. Another small portion runs from the symphysis pubis to the rhomboidal tendon already mentioned. The third portion is deep of the others, and passes forward on each side to the edge of the sternum. The obliquus internus is a well-developed muscle which has an antero-posterior direction. The depressor mandibular differs from that of Rana in that it arises from the skull itself and not from any fascia. The cucullaris is an oblong muscle (it is triangular in Rana guppyi); at its insertion it overlaps the last muscle instead of being overlapped by it as in Rana. The latissimus dorsi has a very remarkable arrangement, which differs greatly from that of Rana guppyi • in the latter it is a long triangular muscle which arises from the middle line of the back and runs nearly parallel with and over the hinder half of the infraspinatus to be inserted in common with it on the humerus. In Pipa the function of the latissimus dorsi is largely assumed by what I take to be the homologue of a portion at least of the obliquus externus. The latter is a fan-shaped muscle corresponding in shape and extent to the abdominal portion of the pectoral on the ventral side of the body. The muscle arises partly from the fascia covering the lateral abdominal region and partly from the great long transverse processes of the sacral vertebrae. It narrows to be inserted on to the humerus in common with the infraspinatus aud partly on to lower border of scapula. Where it passes under the scapula it is joined by a delicate muscle consisting of a few widely separated fibres lying in the fascia covering the scapula. This I take to be the much-degenerated representative of the latissimus dorsi of Rana. It does not, however, blend with the fibres of the external oblique, but ends at right angles to them. It will be noticed, however, that the pull upon the forearm, which is the resultant of these two muscles, would not be widely different in direction from that exercised by the single latissi-mum of Rana. This, at any rate, might well be the case were the muscles equal in strength. I believe, however, that the decay of the latissimus dorsi bears some relation to the different movements |