354 MUSEO NACIONAL DE BUENOS AIRES. 



En iin trabajo sobre la fauna fósil de Puerco, publicado en ese 

 mismo año, los señores Osborn y Earle se manifiestan indecisos 

 respecto á si esa perforación daba paso á un tendón ó á un vaso 

 sanguíneo, inclinándose á creer más probable lo último. « There 

 are two astragali of Periptyclius rhabdodon in tlie collection, and 

 in both there is a plainly marked astragalar foramen; this aperture 

 is situated well toward tlie median trochlear surface, and commen- 

 ces just at the posterior limit of the articular face. The presence 

 of this foramen in reriptijchus is a constant character, and in this 

 respect it differs much from the genus Cor/jphodon, in which it is 

 variable: in both these genera the foramen has the same position, 

 namely, betwen the ectal and sustentacular facets. We doubt whe- 

 ther it transmitted a flexor tendón, as it is not olear how a tendón 

 could traversa thes foramen and then pass outwards under this 

 sustentaculum; it is more likely that this foramen transmitted a 

 blood vessel or a nerve. We are not aware that it exists in any re- 

 cent Ungulate, yet it is a constant character of all Puerco forms, 

 and a vestige of it has been observed by Wortman in the pinniped 

 Carnívora'. » 



El último dato y el más reciente que encuentro })ublicado, es en 

 un trabajo de Matthew, quien en una nota, á propósito de la pre- 

 sencia de la perforación en el astrágalo del género Claenodon dice, 

 que el profesor Osborn ha avanzado la opinión de que la perfora- 

 ción del astrágalo haya contenido una prolongación del ligamento 

 interóseo del seno del tarso. « The use of this foramen seems to be 

 unknown. Prof. Osborn has suggested that it may have held an 

 extensión of the interosseus ligament, which lies betwen the two 

 astrágalo -calcanear facets and connects the astragalus with the 

 calcaneum. If this ligament originally j^assed up to the tibia, its 

 disappearance would be directly connected with the keeling of the 

 ¡Jroximal and flattening of the distal end of the astragalus, all 

 being due to the transference of the main ankle-joint from the 

 distal to the jiroximal end of the astragalus, i. e., the evolution of 

 the mammal from the reptilian stage of development in this cha- 

 racter^. » 



1 Hesry Fairfiííld Osborn and Charles Earle. Fossil Mammnh of Ihe Puerco 

 beds. Collection of 1892, en Bnlletin of Ihe American Museiim of Natural Hiatory. 

 Vol. VII, p. 54, a. 1895. 



2 Matthew, W. D. Addilionat Observalioiis on the Creodonta, en litdl. Amer. 

 Mus. Nat. Hiit. Vol. XIV, p. 16, a. 1901. 



