on Three-toed Sloths. 355 



ratlier tlark-coloured. The liairs of its tlivoat are tipped with 

 white, a point not seen in any other species, thougli probably 

 not of great constancy. Its skull is large and solidly built, 

 and the teeth are distinguisiied by the unusual character that 

 the pseudo-incisor is very large — as large as or even larger 

 than the pseudo-canine, which in turn is small, not exceeding 

 the posterior molars in transverse section. These tooth- 

 ciiaracters are, however, not to be seen in Gray's figure, 

 ■which seems to have been taken from a wrong specimen. 

 But that 46. 7. 28. 24 is the proper type tiiere can be no 

 doubt, as its osteological number, 921. a, is quoted by Gray. 

 In Central America we have B. castaneiceps^ Gray, 1871, 

 of Nicaragua, and B. griseus, Gray, 1871, of Veragua, of 

 which we have no further material, and I can add nothing to 

 Alston^s account of them except to note that Mr. Goldman 

 considers them really distinct, and adds to them a third 

 species — B, ignavits, from Panama and the Atrato River. 

 It is, however, certain that griseus and ignavus at least are 

 very closely allied to B. fiaccidus. It is also to be observed 

 that Dr. Allen has identified a sloth from Rio San Jorge, 

 Bolivar, Culonibin, with Pliilippi's B. fphippiger', and as au 

 example from Condoto, Choco, Colombia, presented by 

 Dr. Hpurrell, agrees with Philippi\s figure in the great size 

 of the speculum, the breadth of tlie frontal band, the distri- 

 bution of the light and dark face-markings, and the size of 

 the teeth, I am disposed to accept Dr. Allen's identification, 

 and put down ejihippiger, which was described without exact 

 locality, as a native of N.W. Colombia, therefore in the same 

 region as " B, ignavus" came from. 



Ill any case, however, the relations to each other of 

 griseits, ignavus, epJiippiger^ and Jiaccidus clearly need much 

 lurtlier investigation. 



B.faccidus, Gray, 1849, has as type-locality Venezuela 

 (probably the region opposite Trinidad), and has as synonyms 

 dysoni, Gray, 1869, and columbicus, Fitz., 1871. 



But by wiiat characters it can be positively distinguished 

 from the Brazilian forms I have not sufficient good material 

 to be certain. 



From Ecuador the Museum contains, firstly, a set of five 

 adults and two young from Sarayacu on the Upper Pastasa 

 River, and, secondly, an adult from the Balzar Mts., Guayas 

 district, W. Ecuador. These appear to me to represent two 

 forms for which no names are available. The first may be 

 called 



