654 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



into long, peg-like protuberances which are directed downward and 

 slightly forward, paralleling and usually closely appressed to the 

 greatly elongated otic bullae; 8, external portion of the mastoid, in 

 the later forms at least, modified into an elongated tube surround- 

 ing the external auditory meatus, but otherwise not much expanded ; 

 9, in the living forms the stomach is simple, except for a more or less 

 developed pouch near its cardiac orifice, and usually more than two 

 young are produced at each birth. 



Family TAYASSUIDAE. 



1, Superficial modifications of feet and skull much as in the Suidae, 

 but with a generally more advanced reduction of the lateral digits, 

 and usually, except in the more primitive forms, with metatarsals 

 III and IV coalesced to form a cannon bone; 2, dental series in 

 general as in Suidae, but with the following constant differences: 

 Premolars except in most primitive forms reduced to f , with tend- 

 ency to great lengthening of diastema behind the canine ; premolars 

 tending to become molarif orm ; molars subequal, not greatly exceed- 

 ing the posterior premolars in size, more simple than is usual in the 

 Suidae; incisors usually reduced or tending to reduce to two above 

 and below ; canines formidable tusks in both males and females, the 

 upper ones being directed downward and slightly outward with no 

 tendency to recurve upward. These are, moreover, usually lanceo- 

 late in cross section when unworn, early becoming triangular as the 

 anterior face is worn away by contact with the lower tusk closing in 

 front of it ; 3, in the more recent forms, at least, lachrymal small, con- 

 fined to the anterior margin of the orbit, allowing a wide contact of 

 the jugal with the frontal; lachrymal foramina reduced or absent; 

 4. zygomatic ridge of the maxillary extending obliquely forward 

 and upward to the side of the face, limiting the backward extension 

 of the rostral sulcus to the region of the infraorbital foramen; 5, 

 basicranial plane bent upward anteriorl}^ at a very considerable 

 angle to the plane of the palate; 6, glenoid fossae extending down- 

 ward and forward well below the basicranial plane, and well sepa- 

 rated from the external auditory meatus by a broad bony expanse of 

 the mastoid; 7, paroccipital processes, so far as known, relatively 

 short, and directed downward and backward nearly at right angles 

 to the long axis of the bullae; 8, mastoid region expanded into abroad 

 thin plate which overlaps and early fuses with postglenoid squamo- 

 sal portion of the zygoma, more or less completely obscuring the ex- 

 ternal form of the elongated tube of the external auditory meatus; 

 9, in the living forms the stomach is complex, and there are nor- 

 mally no more than two young produced at each birth. 



Regarding the validity of the two living genera of peccaries, the 

 following comparative lists of characters seem to distinguish them: 



