104 PATAGONIAN EXPEDITIONS: PALEONTOLOGY. 



Peterson were all obtained on or near the Atlantic coast ; at Coy Inlet, 

 five or ten miles south of that inlet ; at Killik Aike on the Rio Gallegos 

 and two miles west of that point, and at Halliday's Ranch, near North 

 Gallegos. 



Ameghino has named several species upon very incomplete material, 

 which are listed below. 



Thoatherium velatum Ameghino. 



(Plate XIII, Figs. 3, 4.) 



Thoatherium velatum Amegh.; Anales del Mas. Nac. de Buenos Aires, 

 Ser. 3, T. Ill, p. 460. 



Type, an incomplete cranium and isolated .eth. Characterized by the 

 small size of the hypocone in m- and - and the absence of a distinct 

 posterior conule in all the upper molars. M- has no hypocone and the 

 protocone is connected with the postero-external angle of the crown by a 

 curved crest. This species is somewhat larger than T. miuusculum, m- 

 measuring 15 mm. in antero-posterior by 17 mm. in transverse diameter, 

 and in m- these dimensions are 13 by 17 mm. 



Locality. — Rio Santa Cruz. 



Thoatherium karaikense Ameghino. 



(Plate XIII, Fig. 6.) 



Thoatherium karaikense Amegh. ; Anales del Mus. Nac. de Buenos Aires, 

 Ser. 3, T. Ill, p. 454. 



Type, a fragment of the left maxillary with m- in place. This species 

 differs from the preceding ones in the larger size of the hypocone, which 

 is present on m- as an isolated pillar, separated from the protocone and 

 the external wall. This tooth measures 13 mm. antero-posteriorly by 16 

 mm. transversely. 



Locality. — Kar Aike. 



Thoatherium bilobatum Ameghino. 



(Plate XIII, Fig. 7.) 



Thoatherium bilobattmi Amegh.; Anales del Mus. Nac. de Buenos Aires, 

 Ser. 3, T. Ill, p. 459. 

 Locality. — not given. 



