40 SOLENODON PARADOXUS. 



figure uf »S. cubunm. At its proximal eml it is iu cuntact with tlic ulna fur a 

 distance of 6 mm. along the lesser sigmoid cavity. The ulna is more slender in 

 prop(jrti(jns and tajiers distally. At the carpus its cnt;d side is in contact with 

 the radius, antl it articulates with the ulnare. A deep groove commences below 

 the sigmoid notch and runs nearly the entire length of the ectal face, ljec(jming 

 shallower distally. In G^mnura and Erinaceus, skeletons of which were avail- 

 able for tiirect comparison, this groove is but slightly developed. A much 

 shallower groove is present on the ectal face of the ulna, but is Ijarely 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. cubanuti. 



The carjnis of Solenodon (Plate 8, fig. 15) is of a very generalized character, 

 and appears to Ije nt-ai'ly identical in the two specii's of the genus. The jiroxinial 

 row of ossicles consists of radiale, intermedium, and ulnare, the two first of 

 which lie side by side and articulate i)y their proximal faces witli 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 intermetlium. 

 The radiale has the greatest lateral extent of the three, antl 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 jirepollex. The 

 OS centrale is a small com])ressed l)one mainly in contact with the raxliale Ijut 

 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 rejiresents as 

 usual the fused fourth and fifth carpalia; it serves for the articulation of tlie 

 fourth and fifth digits. The first, second, and third carj^alia are separate i^ones, 

 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 jirepollex is about 6 min. long and nearly 2 imn. in greatest 

 width; it is loosely attached by connective tissue at the base of the first digit. 

 The pisiform l)one is strongly developed at the ectal side of the carjjus, and artic- 

 ulates with the ulnare and slightly with the distal jioint of the ulna. 



In the generalized conditi(_)n of the carjjus, 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 scaj)ho-lunar bone") but 

 Peters's figiu'e shows them as two separate ossicles. Gynmura 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. 



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