482 Watson.— On the Structure and 
The important part of M. Renier’s evidence is as follows : 
1. M. Renier has found a specimen of a type which, although not 
common, is still not unusual, in which the quincuncial arrangement of the 
leaf-traces on the trunk is continued on to the area of the scar on an 
internal cast. This is held to show that the inner surface of the scar 
is of the same morphological nature as the inner surface of the outer 
cortex of the trunk. 
Text-fig. r. A diagram of the base of a ulodendroid branch of Bothrodendron, prepared to 
illustrate M. A. Renier’s theory of the origin of the ulodendroid scar. The dotted lines show the 
putative original size of the trunk and branch. Wood, black ; middle cortex left blank ; outer 
cortex with ruled lining. 
2. In a case where both specimen and counterpart of an excellent 
specimen of Ulodendron are preserved, M. Renier points out that the leaf- 
trace scars on any ulodendroid scar of the specimen which is a cast of the 
inner side of the outer cortex do not correspond with those of the reverse 
of the same scar which is an impression of the external surface. M. Renier 
claims that this non-correspondence can only be explained by assuming that 
