417 



2303. The left tibia and fibula of the same Armadillo. A single epiphysis is applied 

 at both their extremities to the shafts of the two bones. 



2304. The bones of the left fore-foot of the same Armadillo. 



The four carpal bones of the proximal row are distinct from one another : the os magnum 

 in the second row has coalesced with the metacarpal of the enormously developed digitus 

 medius. The base of the metacarpal of the index is wedged between that metacarpal, the 

 trapezoides, and the trapezium. The unciforme also supports part of the middle metacarpal 

 as well as the short cubical metacarpus of the fourth finger and the rudiment of that of the 

 fifth. The index digit has three phalanges. The medius and annuhis have each but two, 

 and resemble each other in the character of their modifications, although greatly differing in 

 size. The chief peculiarity, however, in this specimen is the very large sesamoid bone deve- 

 loped in the flexor tendons, and filling the palmar aspect of the fore-foot : a second sesa- 

 moid is attached by ligament to the apex of the large palmar one. 



2305. The bones of the left hind-foot of the same Armadillo. 



The scaphoid is remarkable for its two inferior tuberosities, the interspace between which 

 receives the under part of the entocuneiform bone. The metatarsals and the phalanges of the 

 three middle digits are preserved, with the ungual phalanx of the innermost one or hallux. 



2306. The cranium of the Dasypus minutus; showing the sockets of the eight teeth 

 on each side, of which the first, being behind the premaxillary suture, repre- 

 sents that of a canine. Presented by Charles Darwin, Esq., F.R.S. 



2307. The skull of the Three-banded Armadillo (Dasypus tricinctus). 



. 



The tympanic is a distinct lamina of bone bent in a half-circle : the membrane connecting 

 its inner and under border with the lower part of the petrosal is not ossified so as to form a 

 continuous tympanic bulla, as in the D. Peba. The mastoid is also distinct, is perforated by 

 a vein from the lateral sinus, and terminates below in the usual process. There is no par- 

 occipital. The lacrymal bone is large, and forms a triangular plate upon the face outside the 

 orbit. The alisphenoids join the parietal : the chief expansion of the skull is for the lodge- 

 ment of the large olfactory capsule. There are two small prenasal ossicles. There are no 

 teeth in the premaxillary bones, but nine on each side the maxillaries, and the same number 

 on each side the lower jaw. 



Tftis and the following parts of the same skeleton were 

 presented by Charles Darwin, Esq., F.R.S. 



