IV. VERTEBRATA: MAMMALIA, CARNIVORA 5G5 



of the mammary glands and in the discoidal placenta these animals resemble 

 the primates. Tlie dentition is variable, often i\ll. Fossils occur in the 

 eocene. 



Sub Order I. MICROCHIROPTERA, insectivorous dentition, only the 

 thumb clawed. Vespertilionid^, tail long, no nose leaf; Vcspenigo,'^- Atal- 

 apha.-^ Phyllostomid.e, with nose leaf, tropical America; Desmodiis, blood- 

 sucking or vampyre bat. Sub Order II. MACHROCHIROPTERA (Frugi- 

 vora), smooth-crowned molars, claws on thumb and first two fingers. Includes 

 the flying fo.xcs, Ptcropus, of the East Indies. 



Order IV. Carnivora. 



The carnivores live chiefly on the flesh and blood of other vertcljrates, which 

 they catch by craft, by coursing, or by pouncing upon them. With this mode 

 of life correspond the high development of the brain (fig. 600, B) and sense 

 organs, as well as structure of teeth and claws. Especially striking is the 

 shining of the eyes, especially in the cats (p. 121). Since the predaceous 

 character increases from the bears to the cats, and again tends to disapipear in 

 the aquatic species, there is a great variation in structure. For greater mobility 

 the clavicle is reduced or lost, ulna and radius well developed. In the structure 

 of the feet there is a gradual transition from the plantigrade bears, in which the 

 whole sole rests upon the ground, to the digitigrade cats, which tread on the 

 toes. In the latter the claws, w-hich occur in all carni-.-rires, are kept from 

 injury by being retracted into pockets on the penult join', from which they are 

 extended by strong muscles. In dentition (fig. 6oi) the striking features are 

 the almost constant three incisors, and the great size of (he canines; the molars, 

 on the other hand, vary with the different families, the cusps assuming more of 

 the shearing character {secodont teeth). The last premolar of the upper jaw 

 and the first molar of the lower jaw become carnassial teeth {sectorial teeth), 

 and acquire a dominating position, while the others become smaller and tend 

 to disappear at either end of the series. Further characters are the possession 

 of a penis bone, the abdominal position of the milk glands and the uterus bi- 

 cornis; the placenta is zonary. Anal glands, furnishing a strong, even offensive 

 smelling secretion, are common. 



Sub Order I. FISSIPEDIA. Terrestrial animals with well-developed toes 

 usually cleft to the base. Frequently five digits on all feet, but often reduced to 

 four on the hind feet (Felida:, Canidas), rarely on the fore feet (Hyasnidae); but 

 in these cases (domestic dog) the reduced toe may bear a claw. Ursid.e; 

 Ursus* bears; Procyon lolor* raccoon. Mustelid^; many species of i/zti/e/o* 

 and Putorius* (minks, martens, sable, ermines, and weasels) are valuable for 

 their fur; Lulra* otter; Enhydris* sea otter; Mephitis,'^ skunk; anal glands 

 common, in this family. Fossils (Airlotherium, etc.) connect the bears and the 

 Canid^ five toes in front, four behind, claws not retractile ;Ca«z'5* dogs, fo.xes and 

 wolves. The Felid.e have retractile claws. Felis domeslica, our domestic cat. 

 F. ho, lion; F. tigris, tiger; F. concolor* puma or cougar. Hy^nid^e, all feet 

 four-toed; Flycma of Africa. Viverrid^; Viverra, civets; Herpesies, ichneu- 

 mons. Sub Order II. PINNIPEDIA. Aquatic carnivores with the limbs 

 flattened to broad flippers, the five toes long and webbed, nails frequently 

 rudimentary; the dentition differs from that of the terrestrial forms in the 

 similarity of molars and premolars (absence of carnassial); the milk dentition 

 degenerates, without being functional. Phocid^, seals, no external ears; 

 Phoca vihdma* harbor seal. OxARiiDiE, with external ears; Otaria* sea lions; 

 Callorhimis ursinus, fur seal of Alaska. Teichechid.e; incisors reduced, upper 

 canines developed into large tusks; Trichechus, walrus. The first carnivores 



