{C₁ Five toes, nose prolonged into a { snout _Proboscid′eans_ { {C₂ Toes odd number, less than five _E′quines_ } B₃ { } _Digits {C₃ Toes even number, upper front }_Un- with { teeth lacking, chew the cud _Ru′minants_ } gu- nails or{ }lates_ hoofs_ {C₄ Toes even number, upper front } { teeth present, not cud-chewers _Swine_ } { {C₅ All limbs having hands _Quad′rumans_ { {C₆ Two limbs having hands _Bi′mans_ =Exercise in Classification.=--Copy the following list, and by reference to figures write the name of its order after each mammal:-- Ape (Figs. 405, 406) Rabbit (Fig. 345) Dog (Figs. 356, 408) Hog (Figs. 357, 393) Bat (Figs. 347, 370) Cat (Figs. 337, 348) Armadillo (Figs. 349, 365) Cow (Figs. 344, 386) Walrus (Fig. 340) Monkey (Figs. 352, 401) Horse (Figs. 355, 395) Ant-eater (Figs. 354, 364) Antelope (Fig. 391) Mole (Figs. 367, 368) Beaver (Figs. 372, 373) Duckbill (Fig. 359) Tapir (Fig. 384) Dolphin (Figs. 379, 397) Use chart of skulls and Figs. 381, 382, 395-400 in working out this exercise. =Chart of Mammalian Skulls (Illustrated Study)= 5 1 2 Man’s dental formula is (_M_ -, _C_ -, _I_ -)² = 32. 5 1 2 In like manner fill out formulas below:-- Cow (_M_ - _C_ - _I_ -)² = 32 Rabbit (_M_ - _C_ - _I_ -)² = 28 Walrus (_M_ - _C_ - _I_ -)² = 34 Bat (_M_ - _C_ - _I_ -)² = 34 Cat (_M_ - _C_ - _I_ -)² = 30 Armadillo (_M_ - _C_ - _I_ -)² = 28 Horse (_M_ - _C_ - _I_ -)² = 40 Whale (_M_ - _C_ - _I_ -)² = 0 Am. Monkey (_M_ - _C_ - _I_ -)² = 36 Sloth (_M_ - _C_ - _I_ -)² = 18 Ant-eater (_M_ - _C_ - _I_ -)² = 0 Dog (_M_ - _C_ - _I_ -)² = 42 Hog (_M_ - _C_ - _I_ -)² = 44 Sheep (_M_ - _C_ - _I_ -)² = 32 [Illustration: FIG. 344.--Skull and front of lower jaw of COW.] [Illustration: FIG. 345.--RABBIT. _A_, _B_, incisors; _C_, molars.] [Illustration: FIG. 346.--WALRUS (see Fig. 341).] [Illustration: FIG. 347.--BAT.] [Illustration: FIG. 348.--CAT.] =Chart of Mammalian Skulls= [Illustration: FIG. 349.--ARMADILLO.] [Illustration: FIG. 350.--HORSE (front of jaw).] [Illustration: FIG. 351.--GREENLAND WHALE.] [Illustration: FIG. 352.--AMERICAN MONKEY.] [Illustration: FIG. 353.--SLOTH (Fig. 363).] [Illustration: FIG. 354.--ANT-EATER (Fig. 364).] [Illustration: FIG. 355.--HORSE.] [Illustration: FIG. 356.--DOG. Upper (_A_) and lower (_B_) jaw.] [Illustration: FIG. 357.--HOG.] [Illustration: FIG. 358.--SHEEP.]