i'EiERSON : Mounted Skeleton of Stenomylus hitchcocki. 273 



ciuestion of absence or presence of the groove for the extensor tendon 

 on the upper anterior border of the olecranon process of Steno- 

 mylus gracilis. In describing the ulno-radius (Ann. Car. Mus., 

 \'ol. I\', p. 229, 1910) I stated that the above mentioned groove is 

 absent, which may ha erroneous, since I find that upon very careful 

 scrutiny and by a slow and tedious process of removing a closely 

 adhering silicious si)ot of matrix on the radial face of the process it 

 becomes apparent that this spot is in reality an eroded cavity which 

 was slowh- filled 1)>- this silicious matrix. It is thus clear that the 

 absence or presence of the tendinal groove on the olecranon process 

 of the ulna in S. gracilis cannot be determined from the type specimen. 

 It should also be stated that the trapezium has an articulating 

 surface for the scaphoid instead of one for the scale-like mc. II as 

 stated (/. c, p. 293). 



February 6, igi i. 



