34 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



The ectocuneiform is relatively larger than in Dasypus, though hardly 

 so broad as in Tatu; on the dorsal surface the transverse diameter exceeds 

 the proximo-distal, but the bone contracts much toward the plantar side ; 

 distally, it expands beyond the head of metatarsal III and has a consider- 

 able contact with metatarsal IV. 



The cuboid is quite small, but little exceeding the ectocuneiform in 

 size and of irregularly pyramidal shape. On the outer side is the cal- 

 caneal facet, which is external rather than proximal, almost plane and 

 very oblique, sloping upward and inward and nearly meeting the large 

 navicular facet ; the distal end is principally occupied by the large facet 

 for metatarsal IV, that for metatarsal V being very small. 



As in the armadillos generally, the metatarsus consists of five members, 

 the median three much larger than the laterals (I and V) which are greatly 

 reduced in length, though not in breadth or thickness. In shape and pro- 

 portions these bones most nearly resemble those of Tatu, though they are 

 more massive. 



Metatarsal I is extremely short and heavy, no longer than a phalanx, 

 to which it bears considerable resemblance ; the proximal end has a very 

 large, saddle-shaped surface for the entocuneiform and the distal end an 

 extremely low trochlea, with very short, though prominent, plantar keel. 



Metatarsal II is more than twice as long as metatarsal I and very heavy ; 

 the proximal end is narrow, bears a very oblique and nearly plane surface 

 for the mesocuneiform and rises well above the level of metatarsal III, so 

 as to have an extensive lateral contact with the ectocuneiform ; the shaft is 

 broad and depressed, of somewhat irregular shape, widening to the distal 

 end, which has a very low trochlea, with a median depression on the 

 dorsal side and a prominent keel on the plantar. 



Metatarsal III is the longest of the series and is narrower and thicker 

 than metatarsal II ; the proximal end is slightly broader and considerably 

 thicker than the shaft, which is of nearly uniform width, though broaden- 

 ing somewhat at the distal end, and is of trihedral shape, not compressed 

 planto-dorsally ; the trochlea is well developed, higher and reflected farther 

 upon the dorsal side than in any other member of the series. 



Metatarsal IV is longer than metatarsal II, but considerably shorter 

 than metatarsal III ; it has a broad, very oblique proximal end, which 

 articulates with both ectocuneiform and cuboid, as in /<?///; proximally 

 the shaft is narrow, but thick, but it becomes narrower and more depressed 



