SCALARIFORM VESSELS. 
103 
tremely large, being nearly double the size of those 
of the Brakes already described. 
So characteristic are these vessels among the Ferns , 
that I have more than once identified our common 
Pteris from a small portion of its remains, especially 
in one instance, in which I found some fragments of 
a frond in a funereal urn. About two years since an 
urn, dug up in the island of Anglesey, was, with its 
contents, brought to me for examination by one of our 
most distinguished archaeologists, Mr. Albert Way. 
After having determined the presence of human bones 
belonging to an adult, and to a child, probably a 
mother and her offspring, certain filaments were found 
adhering to the inner surface of the urn ; these were 
of a brown colour, and arranged in definite order 
like the veins of leaves. Upon microscopically ex- 
amining sections of these, scalariform vessels were 
noticed precisely similar to those occuring in the Pteris. 
This Fern is very abundant in the district in which 
the urn was discovered, and most probably, portions 
of fronds were placed in the receptacle before the 
ashes of the deceased persons were deposited in it. 
As I have before remarked, the fact that these 
several varieties in the vascular tissue are dependent 
on modifications in the arrangement of the spiral 
fibre, is proved by the occasional occurrence of several 
of them in one length of vessel or duct; thus in a 
specimen from the Pteris Aquilina (Fig. 91 , b) you 
will observe one vessel, which at its upper extremity 
