2 66 THE GREAT BARRIER REEF. 



picking; a tedious process, but it can be carried into practice with considerable success on the 

 banks, especially with the aid of children, who soon become great adepts in detecting and col- 

 lecting the unwelcome intruder. By such means, the borer has already been fairly exterminated 

 in certain of the most carefully-cultivated banks. This species of boring whelk has been observed 

 in abundance on the oyster-banks, as far north as Rodd Harbour and Seven-mile Creek, where it 

 also levies a heavy toll on the growing brood. The interesting discovery was recently made and 

 communicated to the author by Mr. E. Kelk, of Brisbane, that another gasteropodous mollusc, 

 Nafica pliDiihca, preys upon the Urosalpinx. This species is of larger size than the borer, with a 

 smooth snail-like shell. In the living state, a large fleshy fold, technically termed the " mantle," is 

 protruded from the shell, and forms a continuous border of about an inch in breadth around the 

 creature as it crawls. With this mantle it was observed by Mr. Kelk to seize and envelope the 

 living borer, and to retain it within its folds, until, by muscular force, it had dragged from its 

 shell and devoured its victim's body. Should this recorded habit of Natica plumbca prove, on 

 further investigation, to be its customary one, a valuable remedy for the ravages of the borer will 

 have been discovered in the collection and placing on the beds of quantities of Naticse to devour 

 and keep them in check. Before the application of this specific, it will be desirable to ascer- 

 tain whether, under certain conditions, such as the scarceness of Urosalpinx, the Naticae may 

 or may not develop a latent taste for young oysters. This precaution is the more necessary 

 since, in various standard natural history works, small bivalve molluscs are enumerated as con- 

 stituting the ordinary food of many species of the genus Natica. 



Starfishes of all descriptions, but more especially the ordinary five-rayed varieties, Asteriada?, 

 are universally^ held up for condemnation, as representing the most insatiable foes of the oyster 

 tribe. Whether this wholesale condemnation is a just one, there are some reasons for doubting. 

 In many instances it has been observed that the starfishes were merely acting as scavengers, and 

 preying on dead or dying bivalves. The direct experiment was carried out by the author, some 

 years since, in one of the large English public aquaria, of keeping oysters and starfish, including the 

 accredited most aggressive species, Astcrias ( Uraster) ritbens, in the same tank. The pre-supposed 

 aggressors and their helpless victims were thus maintained, side by side, in perfect health, for 

 many months, without a single instance occurring of molestation of the oysters on the part of the 

 starfish. The Echinoderms, however, demonstrated their possession of normal healthy appetites, 

 by feeding freely on portions of cut-up fish occasionally placed in the tanks. How far this vindi- 

 cation of the starfish's character would hold good in association with the common shore species 

 of South Queensland has yet to be demonstrated. In the interim it is desirable, in the interests 

 of the oyster-grower, to recommend the clearance of this intruder as far as possible from off his 

 beds or banks. In this connection, a suggestion concerning the destruction of starfish may prove 

 acceptable. It is by no means an uncommon practice among oyster-cultivators, on bringing up 

 starfish in the dredge, or finding them on the banks, to rip them in pieces and cast them aside, or 



