40) SOLENODON PARADOXUS. 
figure of S. cubanus. At its proximal end it is in contact with the ulna for a 
distance of 6 mm. along the lesser sigmoid cavity. The ulna is more slender in 
proportions and tapers distally. At the carpus its ental side is in contact with 
the radius, and it articulates with the ulnare. A deep groove commences below 
the sigmoid notch and runs nearly the entire length of the ectal face, becoming 
shallower distally. In Gymnura and Erinaceus, skeletons of which were avail- 
able for direct comparison, this groove is but slightly developed. A much 
shallower groove is present on the ectal face of the ulna, but is barely indicated 
at the proximal end in the two genera Just mentioned. The extreme length of 
the ulna is 54.5 mm., and thus but 2.5 longer than that indicated in Peters’s 
figure, natural size, of the skeleton of S. cubanus. 
The carpus of Solenodon (Plate 8, fig. 15) is of a very generalized character, 
and appears to be nearly identical in the two species of the genus. The proximal 
row of ossicles consists of radiale, intermedium, and ulnare, the two first of 
which lie side by side and articulate by their proximal faces with the radius; 
the ulnare is an isosceles triangle in dorsal outline, and articulates with the ulna 
only at its proximal side, while the base is in contact with the intermedium. 
The radiale has the greatest lateral extent of the three, and at its ental margin is 
produced as a rounded knob on the ventral side. A slight sulcus near the distal 
end of this projection may indicate a fused basal portion of the prepollex. The 
os centrale is a small compressed bone mainly in contact with the radiale but 
on its ectal margin touching the centrale and the third carpale. The distal row 
of carpals is of four bones, of which the most ectal or unciform represents as 
usual the fused fourth and fifth carpalia; it serves for the articulation of the 
fourth and fifth digits. The first, second, and third carpalia are separate bones, 
and give articulation to their respective metacarpals. The second metacarpal, 
however, has also a short articulation at the inner side of its base, with the 
first carpale. The prepollex is about 6 mm. long and nearly 2 mm. in greatest 
width; it is loosely attached by connective tissue at the base of the first digit. 
The pisiform bone is strongly developed at the ectal side of the carpus, and artic- 
ulates with the ulnare and slightly with the distal point of the ulna. 
In the generalized condition of the carpus, Solenodon paradoxus resembles 
Centetes, but is even more primitive in that it retains the radiale and the inter- 
medium distinct instead of fused into one as in the latter. According to Dobson 
these two bones are fused in S. cubanus (‘‘There is a seapho-lunar bone’’) but 
Peters’s figure shows them as two separate ossicles. Gyninura and Potamogale 
in addition to the fusion of these bones, show a further reduction of the carpal 
elements through the loss of the os centrale. 
