80 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



STENOTATUS Ameghino. 



(Plates VI, figs. 19-26; VII, 1-3.) 



Euphractus Amegh., in part; Enumeracion sistematica, etc., 1887, p. 26. 

 Dasypus Amegh., in part; Contrib. al Conoc. de los Mam. Fos., etc., 1889, 



p. 864. 



Stenotatus Amegh.; Rev. Arg. de Hist. Nat, T. I, 1891, p. 253. 

 Dasypus Lydekker, in part; Anales del Museo de La Plata, T. Ill, 1894, 



P- 55- 

 Prodasypus Amegh. ; Enum. Synopt. d. Mamm. Foss. de Patagonie, 1894, 



p. 172. 



This genus is closely allied to Prozaedius, but is, nevertheless, clearly 

 distinguished from it by differences which appear in all parts of the exo- 

 and endoskeleton. 



Exoskeleton. The cephalic shield (Plate VI, fig. 19), like that of the 

 preceding genus, is composed of small, thin, polygonal plates, which are 

 of irregular size and shape and are pitted all over the exposed surface ; 

 they differ in being more coarsely marked and thicker and in having 

 their angles more rounded. 



In the carapace (Plate VII, figs. 1-3) the scutes differ from those of 

 Prozaedius in being larger and very much thicker. The sculpture is of 

 the same general pattern, but with obvious differences ; the plates of the 

 movable bands have the three longitudinal ridges, but they are of nearly 

 equal width and prominence and the lateral ridges are entire, showing 

 hardly any tendency to break up into rows of tubercles, while the median 

 ridge often dies away before reaching the hinder margin of the plate ; the 

 piliferous holes are much better developed, especially in S. hesternus, in 

 which they are very conspicuous ; the marginal scutes are smooth and 

 coarsely pitted. 



The pelvic shield consists of eleven rows of plates and those of the ter- 

 minal row are drawn out into long, blunt spines, like those of the recent 

 Zaedyus, but differently marked. The plates of the pelvic shield are rela- 

 tively shorter and broader than in Prozaedius and have a somewhat differ- 

 ent ornamentation, in that the median ridge does not reach the hinder 

 border of the plate (except in the last three rows), but becomes confluent 

 with the raised posterior margin, thus forming an inverted T, while the 

 lateral and anterior tubercles are larger and less numerous (four or five 

 instead of eight or nine). 



