DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



Limnohyus Marsh, 1872 



The upper molar teeth have the inner cones more elevated 

 and more pointed than in Palaeosyops, and the basal ridge is 

 well developed. The last upper molar has but a single internal 

 cone. The upper canines are large, pointed, and have strong 

 cutting edges. The outer incisors are the largest, and all these 

 teeth have a strong inner basal ridge. The roof of the mouth is 

 deeply excavated between the premolars. The nasals are de- 

 curved laterally and much compressed. 



Cf. Palaeosyops, this monograph, page 331 



Original reference. — Am. Jour. Sci., 3d ser. 

 p. 124, August, 1872 (Marsh, 1872.1). 



Type species. — Limnohyus rohustus Marsh. 



161 



vol. 4, 



Figure 93. — Marsh's type of Telmatherium validus 

 Natural size. 



Measurements [Marsh] 



Millimeters 



Extent of upper molar series : 224 



Extent of upper true molars 130 



Anteroposterior diameter of last upper molar 54 



Anteroposterior diameter of last upper premolar 28 



Transverse diameter 33 



Anteroposterior diameter of upper canine at base 27 



Transverse diameter 22 



Etymology. — validus, strong, stout; perhaps in allu- 

 sion to the large size of the upper canines. 



Generic characters (Marsh). — The term Palaeosyops 

 is restricted to those specimens which, like P. paludo- 

 sus, possess two inner cones on m^ 



The other specimens have but a single internal cone on the 

 last upper molar, and for the genus thus represented the name 

 Limnohyus is proposed. These genera may be distinguished 

 from Telmatherium by the premaxillaries, which are short, 

 stout, and depressed, with a small median suture. 



Etymology. — Xi^ufi?, a marshy lake; Cs, boar. 



Present determination. — Since the type species Lim- 

 nohyus rohustus is now believed to be congeneric with 



Figure 94. — Marsh's type of Limnohyus rohustus 

 Natural size. 



Present determination. — This is a valid genus and 

 species. The name Telmatherium was amended to 

 Telmatotherium by Marsh in 1880 (1880.1) in his 

 "List of genera established by Prof. O. C. Marsh, 

 1862-1879," and the amended form was accepted by 

 Earle, Osborn, Hatcher, and later writers, but accord- 

 ing to the rules of nomenclature now generally ac- 

 cepted the amended form has no standing and the 

 original form Telmatherium should be used. 



Leidy's Palaeosyops paludosus, Marsh's genus Limno- 

 hyus becomes a synonym of Palaeosyops. 



Limnohyus rohustus Marsh, 1872 



Cf. Palaeosyops rohustus (Marsh), this monograph, page 331 



Original reference. — Preliminary description of new 



Tertiary mammals: Am. Jour. Sci., 3d ser., vol. 4, 



p. 124, August, 1872; dated "July 18, 1872" (Marsh, 



1872.1). 



