216 PEOF. E. EAT LANKESTEE ON WALEUS-TUSKS 



information relative to the teeth, but to the teeth themselves, in the sense in which 

 I made use of it fifteen years ago at Prof. Van Beneden's suggestion. 



New Specimens of the Tusks of Trichecus (Trichecodon) Huxleyi, and Comparison of 

 these with the Tusks of Trichecus rosmarus. 



Two of the finest collections of the fossil bones and teeth derived from the base of the 

 Suffolk " Crag," viz. that of Mr. Whincopp of Woodbridge and that of Mr. Baker of 

 Woodbridge, have been broken up and dispersed during tbe last few years ; on the other 

 hand, the Ipswich Museum, which already possessed some valuable specimens, has been 

 enriched by the acquisition of the collection of the Rev. Henry Canham, purchased and 

 presented by Sir Bichard Wallace, Bart., and by specimens presented by Mr. Packard, 

 of Birkfield. The Ipswich Museum now contains the finest series of these remains in 

 any one collection. The two large tusks drawn in PI. XXII. figs. 1 & 2, formed part of 

 Mr. Canham's collection. They are the finest specimens which have been discovered, 

 being nearly complete tusks, and were kindly lent to me by Dr. Taylor, F.L.S., the 

 Curator of the Ipswich Museum, for study and illustration. 



Prom an examination of the large series of tusks of Trichecus rosmarus preserved in 

 the Museum of the Boyal College of Surgeons (for the opportunity of studying and 

 measuring which I am indebted to Prof. W. H. Blower, F.B.S.), I have been able to 

 form some conclusions relating to the absolute size, sectional diameter, curvature, fluting, 

 attrition, and similar points exhibited by these great canines at different ages and in the 

 two sexes. 



Such a series of Walrus-tusks as that in the Museum of the Royal College of Surgeons 

 exhibits a very great variety of forms and sizes ; and the first point to which I have to 

 draw attention is that the variation is precisely parallel to the variation met with in 

 the fossil Walrus-tusks of the Suffolk Crag. The chief differences of form which I have 

 been able to recognize are connected as follows with age and sex : — 



1. Small tusks, almost straight, with unworn points and large pulp-cavity. These 

 belong to young individuals, and may differ a little according to sex. 



2. Pull-sized tusks, more slender and more curved than No. 3. The fluting or ridges 

 on the flattened sides of the tusk much less pronounced than in No. 3. These appear to 

 belong to the females of Trichecus rosmarus. 



3. Pull-sized tusks not longer than No. 2, but less ciuwed and more massive, having 

 a larger transverse diameter and a more decided grooving and ridging of the flattened 

 sides of the tusk. Some of the tusks of this type are nearly straight ; others are slightly 

 curved ; but they appear never to be so much curved as are No. 2. 



•4. Short massive tusks, with the pulp-cavity filled by osteodentine. These are the 

 tusks of old individuals worn down, and exhibit a difference in their transverse section 

 and bulk, according as they have been derived from male or female. 



The differences presented in this series of recent Walrus-tusks is paralleled by those 

 of T. Huxleyi from the base of the Suffolk Crag. 



We have not unfrequently small specimens from the Suffolk Crag corresponding to 

 Group 1 of the recent tusks — that is to say, little or not at all worn, but very slightly 



