Rock-Boring Organisms 



C. M. YONGE, Department of Zoology, University of Glasgow, Glasgow, 

 Scotland 



BEARING in mind the problems presented by this mode of hfe, the 

 habit of rock boring is surprisingly widespread among marine or- 

 ganisms. Among plants, it is found in a variety of green, blue-green, 

 and red algae and also in some fungi. Boring animals include certain 

 sponges, a flatworm ( Turbellaria ) , various sipunculid and polychaete 

 worms, certain echinoid echinoderms, a genus of barnacles, and a 

 diversity of gastropod and, above all, bivalve molluscs. In general 

 these organisms are inhabitants of shallow, most often intertidal, 

 waters. Although of wide occurrence where suitable substrates exist 

 in temperate and tropical seas, they are undoubtedly most abundant 

 on tropical coral reefs and within mudstones in temperate waters. 

 Personal experience of boring organisms has been gained during the 

 course of the Great Barrier Reef Expedition of 1928-1929 and, more 

 recently, on the central California coast while working during 1949 

 and subsequently at the University of California, Berkeley, and at 

 the Hopkins Marine Station of Stanford University at Pacific Grove. 

 The habit of boring is obviously not primitive. The substrate 

 bored is either relatively soft sedimentary rock or else the calcareous 

 product of animal secretion, notably coral skeletons and the shells 

 of molluscs, especially the larger Bivalvia. Certain organisms, it may 

 be noted, such as serpulid polychaetes which secrete a calcareous 

 tube and the neogastropod Coralliophilidae, e.g. Magilus, settle 



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