48 



the astragalus. Molars of upper jaw broad and extending into an 

 externo-anterior angle ; of lower jaw, narrow and continuous in a 

 uniform row. 



TOXODONTIA. (IV.) 



b. 3. Incisors ({) of upper jaw next to symphysis (with persistent 

 pulps) long and curved; those of lower jaw straight and nor- 

 mal. Feet with inferior surfaces furnished with pads, (as in. 

 Rodents and Carnivores): carpal bones in two interlocking rows ; 

 cuneiform extending inwards, (and articulating with magnum,) 

 and affording ail enlarged surface of attachment forwards for the 

 ulna (which is antrorsely produced); unciform and lunar separat- 

 ed by the interposition of the cuneiform and magnum: hind foot 

 with the astragalus at its anterior portion extended and, as a 

 whole, much deflected inwards, articulating in front only with 

 the navicular: toes (four to the front feet, three to the hind) with 

 terminal. phalanges encased in hoofs; (inner nail of hind foot 

 curved). Placenta deciduate, zonary. 



HYUACOIDEA. 



b. 4. Incisors (f, or, in extinct forms, f or f, renewed from per- 

 sistent pulps,) developed as long tusks curved outwards. Feet 

 with palmar and plantar surfaces invested in extended pad-like 

 integuments, which also underlie the toes : carpal bones in two 

 regular (not interlocking) rows, broad and short; cuneiform ex- 

 tended inwards broad, and furnishing an enlarged surface of 

 attachment forwards for the ulna (which is antrorsely produced). 

 Unciform directly in front of cuneiform, and maguum directly in 

 front of lunar: hind foot with the astragalus at its anterior por- 

 tion very short, (convex,) and not deflected inwards, articulating 

 in front only with the navicular : toes (five to each foot, in known 

 forms,) encased in broad shallow hoofs. Placenta deciduate, 

 zonary. Snout produced into a very long proboscis. Legs mostly 

 exserted outside the abdominal integument; and with the proxi- 

 mal and succeeding joints extensible in the same line. 



PEOBOSCIDEA. (VI.) 



B. Posterior members and pelvis more or less completely atrophied ; the 

 form of the body being fish-like, furnished with a horizontal tail, and 

 specialized for progression in the water. Periotic and tympanic bones 

 auchylosed together, but not articulated with the squainosal. 



1. Brain narrow. Skull with the foramen magnum posterior, directed 

 somewhat downwards: supra-occipital nearly vertical and not ex- 

 tending forwards, the parietals meeting and interposed between it and 

 the frontals. Periotic with a posterior irregularly rounded part; 

 tympanic annuliform. Lower jaw with well-developed ascending rami 

 and normal transver e eondyles and coronoid processes. Lateral teeth 

 molar, and adapted to trituratiou of herbage. Neck moderate ; second 



