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 '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 iu position, made by Mr. 

 Salter on the margin of the letter. 



