18/6.] PROF. FLOWER ON MESOTLODON FLOWERI. 485 



ration" 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 second 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 soiverbiensis. 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. soiverbiensis. 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 re- 

 sembling 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 extremities, and - 25 inch in the middle 

 portion. It is rounded posteriorly and flat anteriorly, getting gra- 

 dually 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 Mesop- 

 lodon floweri. By Professor Flower, 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 Pro- 

 fessor 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 speci- 

 men. The latter, however, is a trifle larger in all its dimensions, being 

 an inch and a quarter longer ; and the teeth are rather more deve- 

 loped, probably the effect of somewhat greater age. 



