52 HOMES UNDER THE SEA. 



permit the needful amount of flexibility in the rays. 

 There are many hundreds of these pieces in each starfish. 



And they are arranged in such exquisite order, 

 and produce such harmony of outline, that their beauty 

 is beyond the power of description. A portion of these 

 plates may be seen in Fig. 1. 



That starfishes are destructive to oysters has long been 

 known, but it was thought that in order to reach the 

 oyster the starfish waited until the mollusc opened its 

 shells, and then prevented it from closing them by thrust- 

 ing one of its rays between them. 



Such a process, however, would have been impossible, 

 as the adductor muscle by which the shells are closed is 

 so powerful that the ray would be crushed as soon as the 

 mollusc took alarm. Several instances have been 

 recorded of mice strangled by oysters. The mouse 

 had gained access to a fishmonger's shop, found an 

 oyster with its shells open, and put in its head for the 

 sake of eating the oyster. Directly the mollusc felt the 

 touch of the intruder's teeth, it instinctively closed its 

 shell on the neck of the mouse and so strangled it. 



The real mode by which the starfish attacks, opens, 

 and devours the oyster is as follows : 



First, the starfish clasps its arms round the oyster, so 

 as to bring its mouth against the edges of the shells. It 

 is able to hold itself firmly in its place by means of the 

 ambulacra, each of which is a separate sucker. 



Then from the mouth it protrudes a series of vesicles, 

 one corresponding to each ray. These vesicles are never 



