17 i 



Heiuuaau Pohle: 



opportunity of comparing it. Its differences, excepting size, are 

 trifling. The tubercle for insertion of the quadriceps extensor is 

 less prominent, so as to give the head of the bone proportionately 

 less thickness in relation with its breadth. The ridge for the at- 

 tachment of the interosseus membrane at the lower part of the 

 bone is more prominent and sharper. The distal end in front 

 just above the articulation is flatter/ and the flexor tendous 

 behind is deeper. 



Length of the bone internally 59"'; Width of the head 15"'; 

 Thickness at the inner condyle 10 V 2 " ' ; Width of , the distal 

 end between the most prominent points 11'"; Thickness at the 

 inner malleole 8"'. 



pg. 316. Mustelidae. Lutra? Lutra piscinaria. 

 Indicated by a tibia, described page 230, and represented in Fig. 4, 

 Plate XXXI. From the Pliocene Tertiary of Idaho." 



4. tLutra pristina Matthew et Gidley 



Literatur. Matthew et Gidley [1904]. 



Synonymie, Es ist nur ein Unterkiefer bekannt, dessen 

 Reißzahn noch dazu abgerieben zu sein scheint. Trotzdem ist 

 wohl sicher, daß eine Lutrine vorliegt, vielleicht ein amerikani- 

 scher Ausläufer der Aony x-Reihe, worauf der etwas grubige Talon 

 des mT deuten würde. Genaues läßt sich jedenfalls nicht sagen, 

 ehe nicht besser erhaltene Überreste vorliegen. 



Matthew et Gidleys Diagnose. Lutra pristina. 



The Type is a very perfect lower jaw (No. 10 811 des Ameri- 

 can Museum of Natural History) from the quarry at the Canon 

 of the Little W hite River, S. Dakota. It is considerably larger 

 and more robust than L canadensis, the carnassial has a narrower 

 trigonid with higher Paraconid and Protoconid, Metaconid Less 

 widely separated and somewhat more posterior in position; the 

 heel broader and more basin-shaped, with stronger internal ridge, 

 lower hypoconid and distinct hyloconid. ^2 is of proportionately 

 larger size, the surface flatter, the cusps lower, the outline more 

 regularly circular. The heels of the premolars are narrower than 

 in L. canadensis, with a well-defined cingulum, but no heel-cusp. 

 The angle of the jaw is produced into a short stout process, absent 

 in the modern species; the coronoid process is much wider, espe- 

 cially towards the tip, and directed more backward. The 

 muscular attachment are marked by much stronger ridges 

 and rugosities. 



The carnissial is larger and wider than in L. dubia, with a 

 much broader heel. The metaconid appears to be somewhat more 

 separated, and the paraconid-protoconid shear lower. 



Length of the entire dentition, incisive alveoli to M2 63 mm: 

 Length of premolar-molar dentition P2 — M2 48 mm; C antero- 

 posterior diameter 10 mm, transverse 8 mm; P3 antero-posterior 

 diameter 8 mm, transverse 4 mm; p~4 antero-posterior diameter 



