50 THE ZOOLOGIST. 



The treatment of shells situated in Pholas or Saxicava borings 

 depends on the amount of room around the shells. If there is 

 plenty of room, the shell may be extracted and dealt with as in 

 the other cases, or it may be laid open and cleared of its contents 

 in situ. If the shell is a tight fit so that it can neither be 

 expanded nor extracted, a fragment is broken transversely off 

 the end of one valve (the posterior end) by vigorous lateral 

 leverage, and through the enlarged opening the contents of the 

 shell are removed. 



Pholas crispata. 



On each of several occasions, when watching Oystercatchers 

 at work on the shales, I saw one bore very deeply through the 

 sand-covering portions of the shale, and shake the bill vigorously 

 and repeatedly from side to side in such a way as to suggest that 

 the bill was being resisted laterally by the solid rock. Swallow- 

 ing movements followed in each case without the bill having 

 been withdrawn into view. Though suspecting Pholas, I was 

 unable to exclude the possibility of a deeply seated Tapes. At 

 the same time, I was aware that many borings occupied by live 

 Pholades were wide enough at the entrances to admit freely the 

 bill of an Oystercatcher. The matter was eventually settled by 

 the discovery of a Pholas crispata in a pool not far from an empty 

 boring in the shales, and soon after the Oystercatchers had left- 

 The two valves had been separated, and lay on their external 

 surfaces slightly apart. One valve had been fractured trans- 

 versely an eighth of an inch from the posterior end, which was 

 awanting. Fragments of flesh were still adherent to the valves, 

 showing that the specimen had been recently opened. The 

 entire valve measured nine-sixteenths of an inch in length by 

 seven-eighths of an inch in breadth. The apophyses were 

 intact. 



Purpura lapillus. 



Since the preliminary note relating to this species was 

 printed, " I have examined two hundred and ninety-four shells, 

 all of which bore evidence of having being dealt with by the 

 Oystercatcher. Of these, four (1 per cent.) reached the first 

 stage of opening, and sixty-one. (21 per cent) the second or 

 completed stage, the remaining two hundred and twenty-nine 



' Zoologist,' 1910, pp. 109-112. 



