822 DR. MAXWELL T. MASTERS—A GENERAL 
Histology.—A section across the middle of one of the ultimate 
branchlets, including the lateral and sometimes, as in fig. 6, 
the median leaves also, often reveals the true shape of the leaf 
better than mere inspection of its surface. I have, therefore, 
added plans prepared by Mr. Worthington Smith, from camera- 
lucida drawings, taken from sections made by myself, or, under 
the direction of Mr. Houston, by the pupils of the technical 
laboratory of the Essex County Council. 
Fig. 6. 
Thuiopsis dolabrata.—Section through lateral and median 
leaves and axis, x 20, 
The anatomical details may eventually be made use of for 
specific purposes. I have not ventured to do so at present, for, 
although I have examined the minute structure of the leaf in 
almost all the species, yet the leaves examined have been few in 
number, and they have necessarily been taken from one or two 
specimens only. To be of value the observations require to be 
repeated upon a large number of specimens in various stages of 
growth, and growing under diverse conditions. The anatomical 
structure of the leaves is less sharply differentiated than in 
Pinus or Abies, and is therefore not so suitable for taxonomic 
purposes as it is in the two genera named. In general terms the 
leaf-structure is as follows :—A cuticle covers the whole of tbe 
more exposed parts of the leaves, but is absent from those 
portions appressed to the branch and from the inner surface 
generally. The epidermal cells are very thick on their free walls 
except in the grooves and covered portions, where the epidermis 
is replaced by a growth of minute papules or epithelial hairs. 
Beneath the epidermis, on the outer or dorsal surface, is a layer 
of strengthening cells or hypoderm ; sometimes this is con- 
tinuous, at other times it is imperfect, being present only at the 
corners and exposed places, It usually consists of only a single 
