52 
those obtained in the ordinary situations, but it is worthy of note 
that when they cast their cuticles for the first time after their re- 
moval from the pit, the shed cuticle was of the original pigmentless 
character, while the second exuviation gave a cuticle in each case of 
a yellow brown colour. 
A much larger number of specimens obtained on J uly 28th, were 
placed in an earthenware trough, in a position well shaded from the 
light. A casual inspection from time to time to time showed that 
they were practically unchanged in colour, and on December 1st, a 
more careful examination revealed that they were still very lightly 
tinged with colour, and that the red spots were also quite faint. 
One however, was found to be almost black, and the red marks were 
correspondingly strongly prominent. 
The eyes on the other hand appeared to be unchanged, though 
they had a whitish look in the water. The attempt was made to see 
if the gammarids would take notice of a small object brought near 
to them, and the result certainly pointed to a partial loss of function. 
At all events the object was not observed apparently, but when it 
was brought close to the antennule, the Gammarus suddenly jumped 
and seized it. 
As with other gammarids, the young were observed to take 
shelter under the appendages of the female. 
I had the opportunity, again thanks to Mr. Forster, of visiting 
the gammarids in their home in the pit, and I was then told that they 
were first observed about nine years ago, and at that time in the 
landward workings. They are now found however, in the “ second 
drift,” which is a part of the workings under the sea — to be partic- 
ular, just about under the rocks called the “ Sow and Pigs.” Here 
the pit is about 400 feet below low water level. I was told also that 
the “pit fish” were literally swarming some 4 or 5 years ago, at a 
time when the drainage water was dammed back to provide a supply 
for the stable. Now they are not so common, for a special supply 
of water is led into the pit from the surface, and the gammarids are 
compelled to live in a small runner from 9 to 16 inches wide, and 
rarely of a greater depth than 1 inch. In places a depth of about 3 
or 4 inches occurs, but a heavy deposit of mud tends to make the 
depth very small as stated, and in some parts it dimishes, in fact, to 
of an inch. In this water, which is constantly but slowly running 
and which I found to be brackish, and to have a temperature of 59° F., 
an hour after its removal from the pit, the gammarids live and re- 
produce. A careful examination of the water was made with a view 
