156 PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 



ASTEROSTEMMA DEPRESSA Ameghino. 

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



Asterostemma depressa Amegh. ; Contrib. al Conoc. de les Mam. Fos. de 



la Repub. Argent., 1889, p. 823. 

 Propalceohophphorus australis Mercerat, in part; Rev. del Mus. de La 



Plata, T. II, 1891, p. 35. 

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



Plata, T. Ill, 1894, p. 48. 



Of the three species originally assigned to this genus, only the present 

 one remains, one of the others, A. granata, proving to be synonymous 

 with Cochlops muricatus, while the third has become the type of Meto- 

 Potoxus Icevatus. The following measurements are taken from a photo- 

 graph of the skull in the Ameghino collection above described. 



MEASUREMENTS. 



Upper dentition, length 101 , width 0065 



i, length (z. e., antero-posterior diameter) .004 $-, length 014 



" width (*'. e., transverse diameter) 007 " width 0075 



, length 0075 i, length 013 



" width 005 " width 007 



4, length on , length 0125 



" width 005 " width 007 



A, length 012 Palate, length ? .102 



" width 006 " width at i 014 



&, length 014 " " " 2- 028 



f DCEDICURID^E. 

 METOPOTOXUS Ameghino. 



(Plates XXIV, Ffg. 8 ; XXVIII, Fig. 5 ; XXIX, Fig. 6.) 



Asterostemma Amegh., in part ; Contrib. al Conoc. de los Mam. Fos. de 



la Repub. Argent, 1889, p. 822. 



Metopotoxtts Amegh.; Sec. Censo de la Repub. Argent, T. I, 1898, p. 210. 

 Though still very imperfectly known, this genus is sufficiently well dis- 

 tinguished. The plates of the carapace, so far as they have been re- 

 covered, have an ornamentation like that of Propalceohoplophonts, but 

 with flat or slightly concave central figure and unusually conspicuous 

 piliferous pits. The few isolated scutes of the cephalic shield that have 



