18 



of the mermaid, hence the name Sirenia). Six cervical vertebree. No 

 incisors. (S. Atlantic). Dugong, two upper incisors. Cleft in heart, 

 separating the ventricles. (Indian Ocean.) 



VI. CAENIVORA (flesh-eaters). — Mammals adapted to seizing and 

 killing prey, and to a flesh diet, by (1) sharp claios (mostly); (2) character- 

 istic dentition, long sharp canines, molars with ridges and sharp edges, 

 especially the "sectorial" tooth — teeth enamel coated and diphyodont; 



(3) simple stomach and short intestine (as in flesh-eating animals generally) ; 



(4) prominent sagittal crest between the parietals for attachment of jaw 

 muscles. Complete covering of hair. No clavicles. Manus and pes always 

 loithfive digits. Placenta zonary and deciduate. 



1. FissiPBDiA (cleft-footed).- — Carnivores adapted to a terrestrial life by 



(1) digits being free, i.e. not webbed, and with long claws; (2) hind 

 legs free from the tail. Incisors 3 upon 3. 



[Marsupial Carnivores never have incisors 3 upon 3. ] 



(a) Cynoidea (Dogs). — Digitigrade fissipedia. Claws bluntish 

 and not retractile. Dentition, 3 upon 3, 1 upon 1, 4 upon 4, 

 2 upon 3. e.g. Dog (Canis). 



(h) Arctoidea (Bears). — Plantigrade. Molars tuberculated, suit- 

 able for a mixed diet. e.g. Bear, Weasel, Otter, Badger. 



(c) yEluroidea (Cat family). — Digitigrade. Claws sharp and 

 retractile, e.g. Cat and Tiger (Felidae), Lion, Hyasna (claws not 

 retractile), Civet. 



2. PiNNiPBDiA (web-footed). — Carnivores (mostly marine) adapted to an 



aquatic fish-eating life by (1) all the limbs fin-like; (2) hind limbs 

 united to the tail to form a pi-opeller; (3) digits wehhed; (4) canines 

 recurved, e.g. Seal (Phoca), Walrus (canines form large tusks). 

 Otario (Sea-lion). 



VII. CETACEA (Whales). — Mammals, externally fish-like, adapted to 

 an aquatic life by (1) smooth skin almost hairless, with a thick layer of fat 

 (blubber) underneath ; (2) tail in the form of a horizontally flattened fin, 

 used as a propeller ; (3) fore limbs converted into fins (flippers), hind limbs 

 absent; (4) nostrils (blow-holes) on the top of the head, and valular ; (5) no 

 external ears (absent or rudimentary in all aquatic mammals). Stomach 

 complex. Placenta diifuse. 



1. Mtstacoceti. — Whale-like cetacea. Teeth in the adult are replaced 



by horny plates of " whalebone " (fringed with bristles), which hang 

 from each side of the palate. 6.17. Balasna (Right Whale). 



2. Odontocbti. — Dolphin-like cetacea. Homodont, monophyodont, 



teeth in the adult, and never "whalebone." The skull is often 

 asymmetrical, e.g. Sperm Whale, Narwhal (with horizontal tusk). 

 Porpoise (Phoccena), Dolphin (Delphinus). 



