368 Qtiariirly Jotimal of Conchology. 



NOTES ON BULL/A RHODOSTOMA, Gray. 

 By J. S. GIBBONS, M.B. 



The genus Btdlia, Gray, is well developed in the S. African 

 Seas, there being some 1 2 species inhabiting the sandy shores from 

 low water to a depth of six or more fathoms. B. rJiodostoma is by 

 far the most common, occurring in Yast numbers on the sands 

 between tide marks. It appears to be confined to that part of 

 the coast lying to the eastward of Cape Point, being replaced in 

 Table Bay by a closely allied, but probably distinct species. 



The animal has an extremely large foot, heart shape, Yery 

 broad and thin, deeply cleft in front and of a pale, semi-pellucid, 

 yellowish-grey color. In front rather above the lobes of the foot, 

 and passing through the sinus in the shell is a long, tapering, very 

 mobile, siphonal process, the edges of which are curved round so 

 as to form an almost perfect tube; the mouth is between this 

 process and the lobes of the foot. 



The movements of the animal along the wet sands is rapid, 

 and always within reach of the waves; it advances the two rounded 

 lobes of the foot simultaneously, at the same time slightly drawing 

 them together, and then drags up the shell. The siphon is 

 carried curled backwards, but fully half its length touches the sand; 

 it is continuUy in motion, and serves to scoop and guide a small 

 stream of water into the mouth. The animal does not confine 

 itself to a straight course but turns in various directions, ploughing 

 deepish furrows in the sands. It is very interesting to watch 

 them crawling about in every direction, some large, some small, 

 their peculiar mode of progression, by a series of quickly succeeding 

 spurts, making the spectacle the more singular. Although destitute 

 of eyes, they possess substitutes in a great sensitiveness to touch, 

 and probably an acute sense of smell, and they are certainly more 

 active and shew more intelligence (or its equivalent in the Mollusca) 

 than most members of this class. When lifted off the sands by 



