250 Scientific Proceedings, Royal Dublin Society. 



Pelvis. 



The only difference of proportion seen between the os innominatum of 

 L. europmus and that of L. variabilis is that, in the former, the ilium is 

 relatively broader than in the latter. Judging from the proportional 

 measurements, given in the table, of the pelvis of the young L. variabilis 

 (No. 3283 R.O.S.), the relative breadth of the ilium becomes greater as age 

 advances. 



The outer surface of the ilium in L. variabilis and L. v. arcticus is more 

 boldly sculptured than in L. europceus, the median ridge, for the gluteal 

 muscles, and tlie fossae above and below it being higher and deeper 

 respectively. 



The fossil examples from Ightham agree in these respects with L. variabilis, 

 and are distinguished from the recent specimens only by their large size. 



