ART. 8. THE GENEKA DESMOSTYLUS AND CORNWALLIUS HAY. 5 



the inner end of the same valley is a much smaller tubercle. A single 

 tubercle appears at the outer end of the second valley and is closely 

 api^lied against the hindermost column. The rear of this column is 

 missing. 



There belonged to this tooth quite certainl}^ two roots, but these 

 are broken off (pi. 2, fig. 5). A considerable pulp cavity remains, 

 27 mm. long and 15 mm. wide. It is slightly constricted near the 

 middle of the length, indicating thus the parting of the roots. 



From Director Kermode was received also the tooth which was 

 described and figured in 1917 ^, as Desmostylus hcsperus^ and which 

 Cornwall, in his paper cited, figured as Desmostylus sookensis. It 

 was found in the sandstone cliffs near the mouth of Coal Creek, 

 British Columbia, by Miss M. Egerton. If was sent to L. M. Laiiibe, 

 paleontologist in the Geological Survey, Ottawa, whose remarks on 

 it are published on the page above cited. Mr. Lambe identified it 

 provisionally as tlie upper right first molar. He did this possibly 

 relying on my identification of the first molar in my paper of 1915. 



The length of the tooth (pi. 2, figs. 1-3) is 33 mm. ; the width 24 

 mm.; the height of the crown, 16 mm. It is somewhat more w^orn 

 than the tooth described in the previous paragraph, but it is evi- 

 dent that the columns were originally low. It had two well -devel- 

 oped roots (pi. 2, fig. 3) of equal size. These are now broken off 

 squarely just below the crown. The transverse diameters of these 

 roots are close to 18 mm. At the plane of fracture they are not en- 

 tirely separated from each other. The tooth is supposed to belong 

 to the left side of the lower jaw, because the cingulum is better de- 

 veloped on the left side of the tooth. It consists of six' columns 

 arranged in three transverse pairs. Of the anterior pair the inner 

 column is the largest of all. The inner column of the third pair is 

 very small and the wear had not exposed the dentine. Cornwall, 

 perhaps correctly, did not count it as one of the columns. On the 

 front of the tooth, in the midline, is a broad tubercle which may be 

 regarded as a talon or a part of a cingulum. On the outer face 

 there is a slight cingulum-like ridge at the bases of the two front 

 columns. Between the second and third columns is a tubercle or cusp. 

 On the inner face there is little or no trace of the cingulum. On 

 the front end of this tooth there is an extensive surface polished by 

 contact with a tooth in front. This begins at the level of the grind- 

 ing surface and descends not only to the talon, but in a narrowing 

 strip nearly to the base of the crown. Above the talon the polished 

 surface is 15 mm. wide from side to side. A small polished surface 

 is found on the hinder end of the tooth. 



» Rep. Provijicial Mus. Nat. Hist., Victoria, B C, for 1916, p. 42, pi. 9, figs. 2, 3. 



