1899] Webster, — Hydnum Caput-Medusae 109 
is tuberculiform, has long spines, though shorter than those of the last, 
and finally, as the name would indicate, has a suggestion of the Gorgon 
locks in the distorted character of the upper spines; the Bear's-head 
hydnum, which has a tubercular body like the last two, differs, as is 
easily seen in section, by being covered with short branching processes 
from which the spines depend. 
In Fries's descriptions some prominence is given to the statement 
that Hydnum Caput-Medusae turns smoky or ashen with age, and not 
dingy yellowish or brown like the others, but it must be remembered 
that he admits that up to the time of the publication of his Hymeno- 
mycetes Europaei (1874), he had seen only a plate of this species. 
The others he knew in their growing state, and Æ. Caput-ursi is a 
species of his own making. 
All four species are found in this country, but that the Medusa 
hydnum is not common is plain from the following remarks which the 
writer is permitted to quote from a letter from Professor Peck: “You 
correctly surmise that I have received specimens of Hydnum coralloides 
and 4. Caput-ursi from correspondents who took them to be X. Caput- 
Medusae. I have never seen typical specimens of this species from 
this: country, but I have received from western New York and from 
Missouri, specimens that might be referred to it by some, since the 
agreement was very good except in color. They had spines on the 
upper surface, that by a little stretch of the imagination might be called 
‘contorted,’ though they really were merely wavy or flexuous. In no 
case have these, or any others that have come to me, shown any dingy 
gray or sooty cinereous color, and, as they have indicated a somewhat 
«ramose-cancellate’ structure within, I have considered them only a 
variation of Æ. Erinaceus. . . . In the fifty-first report, which I expect 
will soon be issued [January, 1899] I have given a figure of Æ. Caput- 
urst, asit occurs in our state. I have thought it desirable to do so in 
order to correct the too prevalent false notions concerning it as well as 
to illustrate our edible species.” 
Enough has been said to show that Hydnum Caput- Medusae, how- 
ever definitely imagined, is by no means easily discovered or deter- 
mined when found. It may justly be inferred, moreover, that distinc- 
tions between it and others are not too well known. It is none the 
less deserving or attractive as an object of search. On the contrary 
there is offered to every observer the interesting problem of straighten- 
ing out the difficulties of the case for himself, and of making abundant 
