632 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxii. 



phalanges are armed with remarkably long well-developed digging 

 claws. The first digit is much reduced, but is still functional and bears 

 a long, slender claw. The metacarpals are strongly keeled distally 

 on their inferior faces, but the articular facet is very limited superiorly 

 and locks solidly with the proximal phalanx when fully extended. 

 This, together with a similar construction of the other phalanges, con- 

 stitutes an arrangement of the foot, as a whole, unparalleled in any 

 other group of rodents. The toes were capable of extreme flexing, 

 but this perfect locking prevented them from reflexing except to a 

 limited degree, as shown in Plate LXIV, fig. e. The claws thus per- 

 manently held in a curved position, together with the slight rotary 

 motion possible to the radius and ulna, indicate that the animal walked 

 on the outer side of the foot, with the claws turned inward in a manner 

 somewhat sindlar to the Great Anteater. This position of the foot 

 probably explains also the unusually great extension of the distal end 

 of the ulna below that of the radius. 



In the Spalacidai the general proportions of the bones of the fore 

 limb, except the scapula, are very similar to those «f Epigauhis. The 

 humerus has much the same modifications as the latter, but there is 

 no entepicondylar foramen present in the forms examined. The radius 

 and ulna also are of similar proportions, and the olecranon is long and 

 stout. But the scapula is very unlike in its proportions, being much 

 more slender than in Epigaulus. 



The fore foot of Epigaulus^ with its short digits and long heavy 

 claws, suggests especially the highly modified foot of the Asiatic genus 

 Siphneus^ now called Myotalpa., but judging from the figures published 

 by M. Alphonse Milne-Edwards'^ the distal articular facets of the 

 metacarpals are not limited superiorly as in Epigaulus; hence the toes 

 have more flexibility, and the foot also appears to come naturally into 

 the usual plantigrade position assumed by most rodents in walking. 



Compared with the Mylagaulus pelvis described by Matthew'^ the 

 ilia diverge more anteriorl}^, and the attachment of the sacrum does not 

 extend so far forward. (See Plate LXI, fig. a). The ischium is short, 

 with a heavy tuberosit}^; the light pubes are connected by a slender 

 rod-like symphysis, and the ol^turator foramen is large and broadl}" 

 oval in outline. The pelvis, as a whole, resembles the pelvis of Aplo- 

 dontia more than that of any of the other living forms examined, but 

 it is comparatively shorter and of generall}" more robust proportions. 

 A striking peculiarity of the pelvis is that it is placed at a much 

 greater angle to the line of the vertebral colunm than is usual in 

 rodents. 



« Eecherehes pour servir a I'histoire naturelle des Mammiferea. Paris, 1868 to 1874 

 pi. ixh. 



&Mem. Am. Miis. Nat. Hist, I, Pt. 7, 1901, p. 379, fig. 6. 



