EDENTATA OF THE SANTA CRUZ BEDS. 28 1 



MEASUREMENTS. 



Skull, length in median basal line 136 Distance, condyle to glenoid cavity 027 



Cranium, length occipital crest to edge " " "6- 071 



of orbit 100 Rostrum, width 038 



Face, length from orbit to anterior nares .036 Anterior nares, width 024 



Occiput, height 040 Palate, length in median line 056 



" width at base 055 " width at 1 024 



Cranium, width at postorbital constriction .031 " " " 2- 013 



" " over lachrymals 048 " " " & 012 



Zygomatic arch, length 082 



We may next consider a group of three genera, Schismotherium, Pele- 

 cyodon and Analcimorphus, which are in some important respects more 

 primitive than any of the genera described in the preceding pages ; they 

 agree with one another in certain characters which, at first sight, seem to 

 be very trivial, but are so remarkably constant that they must be regarded 

 as significant. The first upper, or caniniform, tooth is implanted at a 

 greater or less distance behind the anterior edge of the palate, and the 

 second upper tooth, which in all other known Santa Cruz Gravigrada is 

 transversely oval or rectangular, is, without exception, subcylindrical or 

 styliform. The digits of the pes are more uniform in length than in 

 Hapalops. 



ANALCIMORPHUS Ameghino. 



(Plates XLVII-XLIX.) 



Analcimorphtis Amegh. ; Rev. Argent, de Hist. Nat, T. I, 1891, p. 320. 



Ameghino has referred this genus to the Planopsidce (Prepotheriidce 

 Amegh.), a reference which was justified by the similarities of the denti- 

 tion, but the discovery of a large part of the skeleton shows that this 

 genus is an undoubted member of the Megalonyc hides and, in particular, is 

 nearly allied to Schismotherium and Pelecyodon. The type-species, A. 

 inversus, is still very imperfectly known and it remains to be proved 

 whether the second and very much larger species, A. giganteus, is or is 

 not properly referable to the same genus. So far, however, as the known 

 material permits of a decision, there is no reason to separate the two 

 species generically. 



AnalcimorpJms is characterized primarily by the dentition, which has 

 certain marked resemblances to that of the Planopsidce. In the upper 

 jaw - is small, cylindrical, horizontally abraded and inserted far behind 



