FROM THE PHOSPHATE BEDS OF SOUTH CAROLINA. 215 



No remains of an undoubtedly extinct species known to me have been disco- 

 vered anywhere. Dekay (Nat. Hist. New York, Zoology, I., 18-12, p. 56, PI. xix., 

 fig. 1) notices a specimen, consisting of the facial portion of a skull of a Walrus, 

 found on the shore of Accomac Co., Virginia, which he refers to an extinct species 

 with the name of Trichecus mrginianus. He gives as its characters: "Cheek teeth 

 with obliquely truncated crowns, not ridged ; the second smaller than the first." 

 These apply to the recent animal as well, and therefore do not justify the reference 

 of the specimen to an extinct species. 



Among the collection of Ashley fossils of the Pacific Guano Co., submitted to 

 my inspection by Mr. J. M. Gliddon, there is a specimen of a Walrus tusk with 

 perhaps sufficient peculiarity to infer a species different from the living one, though 

 I suspect the peculiarity is of an individual varietal, and perhaps partly of an 

 accidental character. 



The specimen, represented one-third the natural size in figure 6, PI. xxx., is as 

 black as ebony; dense, heavy, and brittle, and has been broken by an accidental 

 bloAv of the shovel into a number of pieces. These have been cemented together, 

 and the tusk appears nearly complete, except at the thin border of the pulp cavity. 

 The inner curvature is slight, and it indicates the tooth to be of the left side. 



In robust character the tusk quite equals those of the largest mature recent 

 skulls which have come under my observation, but is much shorter and more 

 abruptly tapering. The specimen looks like what we might suppose the tusks of 

 the living animal would, were they broken off near their middle and then worn 

 away little more than one-fourth the length in a curved line deflected from the 

 course of the anterior longitudinal convexity to the tip. The comparative brevity 

 of the tusk and its worn condition at the end may perhaps have depended on just 

 such an accident and subsequent wear. 



In a mature skull obtained from the shore of Sable Island, and preserved in 

 the museum of the Academy, the tusks, which are of the usual size, are worn in 

 the same manner as in the Ashley specimen for more than half their length. 



The inner side of the Ashley tusk is fluted in front and behind the middle. 

 The intermediate ridge is the most prominent, and the posterior ridge is further 

 defined by a groove descending and disappearing before reaching the middle of the 

 tusk. The outer side of the fossil is also fluted, though not so conspicuously, and 

 the furrows disappear below the middle of the tusk. The arrangement on the 

 inner side of the specimen resembles that on the outer side of a large pair of tusks 

 in a mature recent skull, contained in the collection of the Academy, more than it 

 does that on the same side of these. The fluted arrangement of the tusks of the 



