154 PATAGONIAN EXPEDITIONS: PALEONTOLOGY. 



Astragalus, length 03 1 5 First phalanx, digit II, width of proxi- 



" width of trochlea 030 mal end 018 



" " head 020 " " " " width of distal 



" thickness of head 0185 end 014 



Cuboid, length 020 Second phalanx, digit II, length oio 



" width 019 " " " " widthofprox- 



" thickness 028 imal end 016 



Metatarsal III, length 037 " " " " width of dis- 



" " width of proximal end. .019 , tal end 016 



Metatarsal III, width of distal end 016 " " digit III, length 013 



" " " " shaft 0125 " " " " width of prox- 



Metatarsal IV, length .031 imal end 017 



" width of proximal end .. .014 " " " " width of dis- 



" " " " distal end 014 tal end 016 



" "shaft 013 Ungual, digit II, length 023 



First phalanx, digit II, length 012 " " " width of proximal end .024 



ASTEROSTEMMA Ameghino. 



(Plates XXI, Fig. 6 ; XXIV, Fig. 7.) 



Asterostemma Amegh. ; Contr. al Conoc. de los Mam. Fos. de la Repub. 



Argent, 1889, p. 822. 

 Propalceohoplophorus Mercerat, in part ; Rev. del Mus. de La Plata, T. 



II, 1891, p. 28. 



Propalceohoplophorus Lydekker, in part; Anales del Mus. de La Plata ; 

 T. Ill, 1894, p. 45. 



The status of this genus is somewhat uncertain and more complete 

 material is greatly to be desired, but, pending the discovery of this 

 material, it seems better to keep the genus distinct, for there is much rea- 

 son to believe that it really is so. 



The plates of the carapace have an ornamentation similar to that of 

 PropalcEohaplophoms, but, so far as they are known, they always have the 

 central figure flat, or even slightly concave, never raised or convex. To 

 this genus I refer a remarkable isolated tail-sheath (Plate XXI, fig. 6) 

 collected by Mr. Hatcher in the Santa Cruz beds on Lake Pueyrredon ; 

 this sheath is quite markedly different from that of any other known glyp- 

 todont. The anterior part of the sheath is made up of movable rings, 

 each with two rows of plates, but in the posterior part the plates are 

 slightly imbricating and while arranged in more or less regular rings, each 

 ring is- composed of only one row of plates, the appearance being more 



