AMEGHINO’S DISCOVERIES 
399 
have partially been accepted also by Dr. Roth,* who has 
personally studied the problems on the spot. 
As regards the mammalian remains contained in the Santa 
Cruz terrestrial beds, Professor Scott f was greatly struck 
by the strangeness of the assemblage. Not a single genus 
occurs in any part of the northern hemisphere. Some of the 
orders even of mammals are distinct from those of the 
northern faunas. Thus the beds have yielded no carnivores, 
no modern groups of ungulates nor elephants, while the 
rodents all belong to the section Hystricomorpha. The place 
of the carnivores was taken by carnivorous marsupials, some¬ 
what resembling the Tasmanian wolf (Thylacinus). Numbers 
of small plant-eating marsupials, of which Caenolestes 
(see p. 350) is an interesting survival, likewise occur. One of 
the largest, most varied and most characteristic elements of 
the Santa Cruz fauna are the edentates. They are repre¬ 
sented by the Dasypoda or armadillos, the greater part of 
whose skin is strongly ossified, the scutes forming a great 
shield over the body, and by the Glyptodontia and the Gravi- 
grada. The last two groups are now extinct. The glyptodonts 
resembled armadillos, except in so far as the bony scutes were 
joined into a solid mass like the shield of tortoises, while the 
Gravigrada or ground sloths were extraordinarily varied and 
numerous. Only a single genus (Necrolestes) of Insectivora 
has been obtained in the Santa Cruz beds, as already alluded 
to (p. 246). At present this order is quite unknown in 
South America. The ungulates belong to the extinct groups 
Toxodontia, Astrapotheria and Litopterna. The toxodonts 
were represented by the genus Nesodon which somewhat re¬ 
sembled a rhinoceros in shape and had similar teeth. Of the 
second group very little is as yet known, while the Litopterna 
are the most remarkable of all the hoofed animals. Without 
being in any way related to the horse-tribe, certain genera 
have paralleled the structure of the horse-foot in a most 
wonderful way, giving the latter a striking and deceptive re¬ 
semblance to that of the ancient Hipparion. The animals 
afford, indeed, as Professor Scott remarks, one of the most 
* Roth, S., “ Sedimentablagerungen in Patagonien.” 
t Scott, W. B., “Mammalian fauna of Santa Cruz,” pp. 242—247. 
