47 



a. Digits with corneous appendages developed as claws (i. e. com- 

 pressed) or, attypically, as nails (i. e. depressed). Teeth of three 

 kinds, (canines of second set etypically atrophied,) all encased 

 in enamel ; (molars mostly two- or three-rooted). Placenta decidu- 

 ate, discoidal. 



PRIMATES. (I.) 



2. Legs with the proximal joints (humerus and femur) more or less 

 inclosed in the common abdominal integument. First digit of hind 

 foot attypically reduced or atrophied ; etypically hypertrophied (e. g. 

 Pinnipedia). Brain with no calcarine sulcus. (Incisors archetypically 

 six in each jaw; etypically, two or more suppressed. Clavicles 

 rudimentary, or in (b) Ungulate Series none.) 



a. Digits with corneous appendages developed as claws. Teeth of 

 three kinds, all encased with enamel : canines specialized and 

 robust : (molars mostly two- or three-rooted etypically one-root- 

 ed, attypically one (- ^) or more in each jaw sectorial, followed 

 by tubercular ones.) Scaphoid and lunar consolidated into one bone. 

 Placenta deciduate, zonary. 



FERAE. (II.) 



b. Digits with corneous appendages developed as hoofs. Teeth of 

 three kinds, (canines and incisors of second set exceptionally in 

 part undeveloped,) all encased in enamel : (molars attypically two- or 

 three-rooted, attypically with grinding surfaces.) Scaphoid and 

 lunar separate. Placenta diversiform. 



b. 1. Incisors (archetypically ; often, especially in the upper jaw, 

 reduced in number or wholly suppressed ; implanted by simple 

 roots,) with incisorial crowns. Feet with inferior (or, rather, pos- 

 terior) surfaces with a hairy skin continuous with the rest of the 

 integument: carpal bones in two interlocking rows; cuneiform 

 narrow and affording a diminished surface of attachment forwards 

 for the ulna (which is retrorse beside the radius); unciform and 

 lunar articulating with each other and interposed between the 

 cuneiform and magnum: hind foot with the astragalus at its an- 

 terior portion scarcely deflected inwards, articulating more or less 

 with the cuboid as well as navicular: toes (not more than four 

 completely developed) with terminal joints encased in thick 

 hoofs. Placenta uon-deciduate, (diffuse or cotyledonary). 



UNGULATA. (III.) 



b. 2. Incisors (f or f ; variable as to insertion,) with incisorial 

 crowns. Feet mostly unknown: carpal bones unknown: hind 

 foot with the astragalus at its anterior portion inclined obliquely 

 inwards, articulating in front only with the navicular. Calcaneum 

 with an extensive upwards surface for the articulation of the 

 fibula, and with a large lateral process articulating in front with 



