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Show 888 MR. ST GEORGE MIVART ON THE [Dec. 6, The musculo-cut ant ous(1) nerve descends between the flexors and the tibialis anticus, becoming superficial at the ankle. The anterior tibial nerve quits the one last noticed, and dipping between the popliteus and the flexor longus hallucis, comes out on the front of the leg above the peroneo-tibial, supplying the extensors. SERIAL HOMOLOGY OF THE APPENDICULAR MUSCLES. The question of the serial homology of the limbs has been lately considered by Professor Flower in his first course of Hunterian lectures *. He there followed out and developed certain views which I suggested in 18661", and which had more or less commended themselves to Professor Rolleston+• I allude especially to the notion that the gluteus medius and minimus are the serial homo-lcgues of the subscapularis, and that similarly the iliacus is the serial representative of the supra- and infraspinatus. Against this Professor Humphry has quite recently raised some objections §, principally opposing any supposed rotation of the ilium similar to that which the whole pelvic limb undergoes during its development. But in reply it may be said that a rotation of the ilium or scapula is by no means necessary to the view I before advocated. In speaking of such a possible rotation in connexion with the Echidna, I did so in deference to the authority of Professor Humphry, who had said || of the ilium and scapula, " it is probable that they also participate, to some extent, in tbe rotation which the limbs undergo." All that is necessary to conceive is that bony ridges are developed in one case which are suppressed in another, not that there is any rotation. This was in my mind when I said **•[[, " on the whole, I am inclined to believe that extended investigations will show that the scapula and ilium may most conveniently be regarded as, so to speak, essentially columnar bones, such as we find them in Chelonians, and serving to give origin to muscles inserted into the proximal bone of each limb, but varying in shape and size, and developing ridges or processes according to the exigencies of each case." For this it is not necessary to suppose any alteration in the ventral parts of the limb-girdles. The singular limb-structure of the Chameleon, and the more than usual resemblance between the ilium and the scapula, made me look forward with great interest to the investigation of its myology. * See also his paper in the ' Cambridge Journal of Anatomy and Physiology ' for May 1870, p. 230, and his recent ' Introduction to the Osteology of the Mammalia,' chapter xx. p. 326. t Trans. Linn. Soc. vol. xxv. p. 305. \ Trans. Linn. Soc. vol. xxvi. p. 620. § ' Cambridge Journal of Anatomy' for November 1870, p. 67. || " Observations on the Limbs of Vertebrate Animals" (1860), communicated to the Cambridge Philosophical Society. ^f Trans. Linn. Soc. vol. xxv. p. 401. |