204 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



more usually the latter continued in active operation ; and if the 

 animal were only just covered by the water a stream would then be 

 projected for an inch or more into the air. 1 I never observed the 

 proboscis to be everted during life, though at death it was protruded ; 

 and the ctenidium was never extended beyond the mantle in the 

 manner shown in Cuvier's figure. The crescentic head-shield was 

 evidently very sensitive, more especially its terminal horns : it was 

 usually carried a little in advance of the body and the villi clothing 

 its under surface were in continual motion. The general colour effect 

 of the upper surface of the animal was that of a pale lilac-brown 

 ground with large and conspicuous black blotches scattered upon it. 

 Examined more carefully, a considerable difference became noticeable 

 between the ground colour of the notaeum and head- shield, and that of 

 the dorsal surface of the foot : the former region being almost yellowish 

 and the spots scattered over it of a deep brown, the latter lilac with 

 purple-black spots. In each case the ground colour shaded off so as 

 to form a well-marked paler zone surrounding each of the maculations. 

 These latter were very variable in form and size ; with irregularly 

 rounded outlines, but having their margins perfectly well defined. 

 A narrow, colourless, and transparent zone extended along the thin 

 edge of the foot. The sole of the foot, which was distinctly tripartite, 

 was of a reddish violet colour, paler towards the centre, but very dark 

 at the edge and posteriorly. The under surface of the head reddish 

 brown with a white margin ; the villi colourless. The lower surface 

 of the mantle colourless. A broad black band encircled each of the 

 rhinophores and the excurrent siphon : beyond this terminally they 

 were an opaque-white. 



During a stay of nearly three years in the Straits I saw but the 

 single specimen here recorded ; and none of the natives employed in 

 the Pearl-fisheries who saw the animal during life, or to whom 

 I showed drawings of it, had apparently ever met with it. Euselenops 

 cannot therefore be at all a common form in this region, and my 

 specimen was possibly only a wanderer from the Indian Ocean. 



1 Adams & Eeeve state that the siphonal inflection of the mantle "guides the 

 water into the marginal groove between the dilated foot and mantle " ; it, of 

 course, is really excurrent in function. 



