INIA GEOFFRENSIS AND PONTOPORIA BLAINVILLII. 105 
flattened, and not much expanded in width, The inner surface is quite smooth and 
slightly concave longitudinally. The outer surface is rougher, and has a rather deep 
pit a little way below the neck. 
The radius and ulna are considerably shorter than the humerus, contrary to what 
obtains in most Cetacea. ‘They are very simple, broad and flat bones, but have a con- 
siderable space between them, owing to the concavity of the contiguous borders of the 
ulna and radius. The ulna presents the great peculiarity of possessing no rudiment 
of an olecranon process. 
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The carpal region is large, and composed in the present specimen in great measure 
of cartilage. ‘There are five principal ossifications. Intending to discuss fully the 
homologies of the carpal bones of the Cetacea with those of the terrestrial mammals 
in my Osteography of the genus Physeter, I will only say here that these appear to 
represent :—1 the scapho-trapezium, 2 the lunar, 3 the cuneiform, 4 the unciform, 
and 5 the magno-trapezoid. They have probably been somewhat disturbed from their 
natural position by unequal shrinking of the surrounding cartilage in drying. In 
addition to these five, an oval bone (6) projects from the ulnar border of the carpus, 
which must represent the pisiform bone, although considerably displaced from its 
normal situation. The bone which appears to belong to the second row of the carpus 
near the radial border, and which might well be taken for a trapezium, is probably 
the first metacarpal, as already determined in other Cetaceans by Cuvier, Gegen- 
baur, and Van Bambeke. 
The digital portion of the hand consists of five fingers of moderate length, and 
spreading somewhat from each other. The second digit is the longest, the third nearly 
approaches it, the fourth and fifth are much shorter. It is possible that the terminal pha- 
langes of the digits are not present in every case, especially as they do not always ossify 
before the animal has attained a considerable age; but the following are the numbers of 
the phalanges present, exclusive of the metacarpals:—I. 1, II. 5, II. 4, IV. 2, V. 2. 
The individual phalanges are thus not numerous; but they are long in proportion to 
their breadth. 
From the humerus downwards the pectoral limb of Jnia presents considerable re- 
semblance to that of Platanista, both agreeing in the great length of the humerus as 
Q 2 
