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Show 1876.] PROF, FLOWER O N MESOPLODON FLOWERI. 485 vation in its upper, and a shallower one in its lower portion. Similar excavations exist in the three other segments, by which three fenestra of a rounded shape are formed. There are five articulating surfaces on each side for the sternal ribs-the first near the upper portion of the first segment, the second at the junction of the first and seeond segments, the third at the junction of the second and third segments, the fourth at the junction of the third and fourth segments, and the fifth at each side of the fourth segment on its lower portion. Pectoral Limb. The scapula is remarkably flat, and without prominent ridges, so that there is scarcely any sign of the postscapular fossa. In form it resembles that of Mesoplodon sowerbiensis. The acromion is broad, and has an upward slope in its anterior portion ; the coracoid is flat and narrow, but widens considerably at its extremity, where it assumes a prismoid form. The humerus, ulna, and radius resemble also considerably those of M. sowerbiensis. The epiphyses on both extremities are so well anchylosed that scarcely the line of junction can be traced. The elements of the carpus are, with the exception of the magnum and trapezoid, which are united into one bone, all separate, thus resembling also M. sowerbiensis and the New-Zealand Epiodon. The same appears to be the case with the digits, which, however, have somewhat suffered, as the pectoral fin had been much lacerated before the skeleton was secured. Pelvic Bone. The pelvic bone for the attachment of the crura of the penis is of small size, and of rather irregular form. It is 4 inches long, 0*37 inch broad near both extremLies, and 0*25 inch in the middle portion. It is rounded posteriorly and flat anteriorly, getting gradually flatter as we reach the lower end of the bone. It is very light and spongy. 4. Remarks upon Dr. von Haast's Communication on Mesoplodon floweri. B y Professor F L O W E R , F.R.S. On comparing the excellent photograph sent by Dr. v. Haast of of the skull of this animal with the type specimen of M. layardi, from the Cape of Good Hope, in the British Museum, neither Professor Van Beneden nor myself could detect any differences of the slightest specific importance; indeed at first sight we were inclined to say that the photographs might have been taken from that very specimen. The latter, however, is a trifle larger in all its dimensions, being an inch and a quarter longer; and the teeth are rather more developed, probably the effect of somewhat greater age. |
