SPECIMEN8 OF LYGINODENDRON OLDHAMIUM. 351 
Ford specimens were ultimately investigated, and are described in the present 
paper. 
The original block of the University College specimen was 42 inches long, 
and had been eut to form a series of thirty-eight slides, thus averaging one 
section to every 4 inch length of the specimen. The outline of each section 
of the stem with its attendant branches and petioles was traced by placing 
Fra. 2. 
Ground-plan of University College specimen ; constructed from the model. 
Six leaves are borne by the main axis— five of these subtending axillary branches. 
None of the branches show further ramification. 
the slide, covered with tracing-paper, against a window. This was, perhaps, 
the most ticklish part of the whole process, because it was often not easy to 
be certain whether a particular branch or petiole belonged to the specimen 
under consideration or not. The difficulty was increased by the fact that 
sometimes, owing to bad preservation, a particular part would disappear from 
one or more slides only to reappear later on in the series, when it was not 
