GENEEIC DISTINCTIONS OF PEOBOSCIDEA. 13 



Mastodon Sivalensis, although with five-ridged ' intermediate 

 molars,' is provisionally included under Tetralophodon. 



Genus Elephas (Linn.). 



Form. Dent, decid. — Primor. -r ; Lan. — ; Mol. =-= 7 . 

 Form. Dent, persist. — Primor. ^ ; Lan. x- ; Prwmol. 2 vel 



|; Mol. 4 = 11-7. 



Primores eburnei plerumque exserti, sursum et antrorsum 

 adscendentes. Molares aut complicati aut lamellosi, 

 tritores ; coronidis longitudinaliter integrse colliculi con- 

 vexi e tuberculis mammillaribus, aut laminis cunei- 

 formibus vel compressis digitatis transversis, constantes : 

 adamante illis crasso, his attenuato, cwmento in valliculis 

 copioso. Prwmolares rarissime utrinque 2 (ssepiusnulli), 

 cseteris forma simpliciores, minores. Molares veri 3, 

 deinceps majores, altero alteram extrasum a tergo 

 vicissim excipiente, demum utrinque solitarii. — Molares 

 3 utrinque intermedii (nempe deciduorum postremus et 

 verorum antepenultimus penultimusque) colliculis supra 

 5 (6-18), aut hypisomeris, aut anisomeris. 



Proboscis longissima, prehensilis. Corpus vastum artubus 

 elevatis insistens. Pedes 5-dactyli. 



Subgen. 1. Stegodon. — Dentium molarium 3 utrinque 

 intermediorum coronis complicata colliculis 

 hypisomeris (e.g. 7 + 7 + 8), mammillatis, 

 tectiformibus. Prsemolares nondum observati. 



Subgen. 2. Loxodon. — Dent, molar. 3 utrinque inter- 

 medior. coronis lamellosa colliculis hypisomeris 

 (e. g. 7+7 + 8), cuneiformibus. Prsemolares 

 raro utrinque 2. 



Subgen. 3. Euelephas. — Dent, molar. 3 utrinque inter- 

 medior. coronis lamellosa colliculis deinceps 

 numero auctis, anisomeris (e. g. 12 + 14 + 18), 

 attenuatis, compressis. Prsemolares nulli. 



Observations. — The adult dentition of the Elephants, 

 although typically more aberrant, is more constant than 

 that of the Mastodons. Inferior incisors are wanting in all 

 the species, fossil and recent, at present known ; and pre- 

 molars have as yet only been met with in a single form, 

 E. (Loxodon) planifrons. The common formula is, Incis. 



- : Can. - ; Premol. - : Mol. T = 7 : but in this exceptional 



ij o x 



case, the premolars are as numerous as in any species of 



