523 MAMMAUA. ^ 



Family I. — Sirenia. 

 Herbivorous Cetacea. 



Molars flat in the crown ; some species are furnished with 

 tusks in the upper jaw ; two pectoral teats ; mustachios ; nos- 

 trils, properly so called, placed at the end of the muzzle ; nasal 

 apertures situated in the upper part of the head ; body massive. 



Genus 1. — Manatus Linnceus. 



Generic Character Incisors '^, no canines, grinders ^-| ; to- 

 tal 38. The incisory teeth are very small, and exist in the 

 foetus only; adults having only 32 teeth, four of the molars be- 

 ing lost while young; grinders with two transverse inflated 

 ridges ; head not distinct from the body ; mustachios formed by 

 a bundle of very stifl" hairs directed downwards, forming a kind 

 of corneous tusk on each side ; eyes very small ; tongue oval ; 

 on the margins of the pectoral fins are rudimentary nails ; cer- 

 vical vertebrce six ; sixteen pairs of thick ribs. 



Manatus Senegalensis. — The Senegal Manatus. — Plate 

 XXV. fig. 1 See vol. II. p. 397, &c. 



Genus 2. — Halicore. — Cuvier. 



Generic Character. — Incisors ^, no canines, grinders |j ; to- 

 tal 14, in the adult ; but in the young the incisors are ^, no ca- 

 nines, grinders l:^ ; total 32. Two upper incisory teeth cylin- 

 drical, straight, forming real tusks ; grinders cylindrical, adults 

 having only three on each side; body pisciform, terminated by 

 a horizontal two-lobed fin ; muzzle truncated and moveable ; lips 

 with thick spiny hairs ; tongue soft ; fins short ; no distinct fin- 

 gers or nails ; cervical vertebroe seven ; eighteen pairs of ribs. 



Halicore Indica. — The Dugong. — Upper jaw with two short 

 straight tusks, directed obliquely downwards ; lips gross, spin- 

 ous ; tail bilobate ; of a bluish-gray colour. Seven or eight feet 

 long. Inhabits the Indian Seas. 



Genus 3. — Stellerus. — Cuvier. 



Generic Character. — Devoid of incisory or canine teeth, grin- 

 ders J— J ; total 4. Teeth not implanted in the jaws, but at- 

 tached to a molar plate on each side, by vessels and nerves ; 

 grinders with tortuous surfaces ; body ventricose towards its 



