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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. 
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 calearine 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—etypicaliy 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. 
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 non-deciduate, (diffuse or cotyledonary). 
UNGULATA. 
b. 2. Incisors (% or 4; 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 withthe navicular. Calcaneum 
with an extensive upwards surface for the articulation of the 
fibula, and with a large lateral process articulating in front with 
(I.) 
(I1.) 
(I) 
