THE ZOOLOGIST 



No. 860.— February 15th, 1913. 



FURTHER OBSERVATIONS ON THE FEEDING HABITS 



OF THE OYSTERCATCHER (HMMATOPUS OSTRA* 



LEGUS). 



By J. M. Dewar, M.B. 



Mytilus edulis. 

 In a previous paper" I gave the results of my observations on 

 the manner in which the Oystercatcher feeds upon the Edible 

 Mussel. There are, however, one or two matters to which it is 

 necessary to return and some new observations to record. I 

 stated that of Mussels buried under sand, as a rule only those 

 are opened which present the ventral fissure, and at the time I 

 expressed reasons for this limitation which further experience 

 has confirmed. On another page I unwittingly created the im- 

 pression that all Mussels under sand or mud are placed in a 

 vertical position. This is, of course, not always the case. The 

 meaning I intended to convey is that those Mussels which are 

 placed in a vertical position under sand or mud must be opened 

 through the posterior ends, owing to the presence of the mud 

 which prevents the Oystercatcher from reaching any other part 

 of the Mussel quickly enough to separate the valves. To this 

 extent buried Mussels differ from those situated on the exposed 

 banks where a Mussel, though it happens to rest in a vertical 

 position, is not necessarily opened through the posterior end. 



When watching the Oystercatcher engaged in turning over 

 Limpets, I was much impressed by the nature of the preliminary 

 * " Notes on the Oystercatcher " (' Zoologist,' 1908, pp. 201-212). 

 Zool, 4th ser. vol. XVII., February, 1913. E 



