1. MANATUS. 357 



Manatina, Reichb. Syn. Mam. 15. 

 Les Lamantins, Dnvernoy, Tab. Anim. Vert. 

 Tricliecus (part), Artecli, Gen. Pise. 79 ; Syn. 109. 

 Halicorese, Brarult, Mem. Acad. Petersb. 1833, 103. 

 Rytinese, Brandt, I, c. 1833, 103. 



Synopsis of the Genera. 

 Grinders distinet. Manatina. 



1. Manatus. Tail rounded. Grinders \ or f , tubercidar ; upper cutting- 



teeth moderate. 



2. Halicore. Tail forked. Grinders f , fiat-tipped ; upper cutting-teeth 



produced, tusk-like. 



Grinders ?ione. Rytinina. 



3. Rytina. Tail forked. Grinders none. 



a. Grinders distinct. Manatina. 

 1. MANATUS. 



Cutting-teeth 2, very small, rudimentary, early deciduous. Canine 

 none. Grinders | . |-, with two or three transverse three -tubercled 

 ridges. Lips bristly. Back with scattered hairs. Fins with four 

 rudimentary hoof-like nails. Toes supported with phalanges. Tail 

 rounded or truncated at the end. Pelvic bones deficient (?). Caecum 

 bifid at the tip. Cervical vertebrae 6, separate, distant. 



Sirenia dentigera seu Halicorea, Brandt, Sirenoloc/ia, 1847. 

 Manatus, Rondel. Pise. 490; Storr, Prodr. 41, 1780; Cuvier, R. A.; 



Illiger, Prodr. 140, 1811 ; Rafin. Anal. Nat. 61, 1815 ; Gray, Cat. 



Cetac. B.M. 139; P.Z.S. 1857,59; 1864,247; Rousseau, Mag. Zool 



1856, 293 ; Schleyel, Abh. 9. 

 Trichechus, sp. , Li'nn. S. N. ed. 6. 39, ed. 10, ed. 12 ; Erxleb. 3Iamm. 599. 

 Odobenus (pars), Brisson. 



Trichecus manatus, Oken, Lehrb. Nat. 687, 1815, 

 ? Nemodermus, Rafin. Anal. Nat. 60, 1815. 

 Oxystomus, G. Fischer, Zoogn. 19. 

 ? Siren, Artedi, Gen. Piscium, 81, from Svrene ; Bartholini Hist. Anat. 



Bar. 

 Trichechus, Artedi. 



The number of grinders varies according to the age or state of the 

 specimens. "When complete they are f . | ; but the three front on 

 each side are often deciduous ; hence Home (Phil. Trans. 1821, 390) 

 describes them as 4 . -I, and Cuvier as -I • I-- 



Dr. Harlan obsei'ves : — " Cuvier estimates the teeth at 36, nine 

 on each side ; in both my specimens they do not exceed 32, eight on 

 each side." 



In the very young skull in the British Museum, which has holes 

 for the rudimentary upper cutting or canine teeth, there are only 24, 

 viz. six on each side ; and the two hinder on each side must have 

 been hidden in the gums. In the older skulls some have eight and 

 others nine on each side ; but in most of them only six on each side 



