256 
Boodle and WorsdelL On the 
the protoxylem, narrower vessels were found with many 
perforations on their end-walls. These perforations were 
extremely interesting, for they were of very irregular shapes, 
this being due to the fusion of the bordered pits in twos and 
threes, or more, as they lay irregularly scattered on the wall, 
to form the perforations, fusing sometimes at an oblique 
angle, sometimes horizontally, or both combined (Fig. 43). 
In some cases the narrow extremity of a perforation was 
occupied by one of these bordered pits still unabsorbed, but 
forming a continuous portion of the perforation (Fig. 44). 
We also saw cases of the fusion of these perforations with 
those above and below, thus indicating, how from several 
perforations, one single narrow oblique perforation is eventually 
attained (Fig. 43). These vessels are precisely similar to 
those described above in Casuarina muricata , Roxb. The 
bordered pits of the vessels differ somewhat from those of the 
other genera in being perfectly round in outline, with a cir- 
cular opening, giving a characteristic appearance. The fibrous 
tracheides here are similar to those in some of the others ; 
the borders of the pits are little developed, and the wall of 
the element is not so very much thickened. In the sieve- 
tubes are numerous plates on a very oblique wall. 
In Carpinus cordata , Blume, the structure of the wood 
differs considerably from that of C. Betulus , L. Indeed the 
structure is almost a reproduction of that of Corylus 
Avellana , L. All the vessels have several perforations, re- 
sembling in every respect those in Corylus. This plant agrees 
better in its anatomy with Corylus than with Carpinus 
Betulus , L. 
Corylus Avellana , L., showed vessels which had terminal 
walls with exclusively several perforations. There are also 
tracheides. An extremely interesting transition was observed 
on the terminal wall of one of these latter : at each end was 
a great number of closely-placed bordered pits ; towards the 
centre these were seen fusing in twos and threes, forming 
a few elongated, slit-like bordered pits (Fig. 45). It will be 
seen that this is a transition from a trachcide to a vessel. 
