APPENDIX. 
347 
B. 
CAMPTOCERCUS FURCATUS. 
The figures of this species, represented in Tab. XXX, 
figs. 4, 5, 6, made by Mr. Salter, were accompanied by 
some very interesting notes, from which, with Professor 
Bell’s kind permission, I make the following extracts : 
“ It is scarcely more than visible to the naked eye. Its 
head and shoulders are covered with a single case, which 
seems a sort of carapace ; below this are three imbricated 
rings with concave edges, looking towards the tail, their 
angles projecting and forming sort of teeth. To the last 
of these is appended the tail, composed of six pieces, 
flexible, capable of lateral and, I think, vertical movement. 
In the centre of the front of the head is a reddish-purple 
spot, which shines very much in some lights, and looks 
like a single eye. The most remarkable thing about this 
little creature is its extraordinary power of movement, 
which is well provided for by three pairs of strong oar- 
like legs, which it casts behind it with great force, throwing 
itself forward with surprising velocity, and outstripping 
even the little sand-hoppers that hunt it. These legs, 
when in a state of rest, are bent up under it, and when 
it means to throw itself forward, it bends backward that 
part of its leg which pointed forward, keeping the other 
part in the same direction ; thus £ a’ is brought to £ b’, 
£ c’ to £ d,’ and c e’ to £ f,’* the oblique direction of the 
other part being, as I said, still maintained. As these 
legs are webbed with hairs, the three present a broad 
surface against the water. When the extension is com- 
pleted, I have no doubt that the muscular action which 
kept the fixed direction of this last joint is relaxed, and 
it is drawn up in such a way as shall present the least 
resistance to the water. There are also two little pro- 
* This refers to a slight sketch of these organs in position, made by Mr. 
Salter on the margin of the letter. 
