1919] Burrows: Occurrence of a Rock-Boring Isopod 303 



Charles Hedley (1901, p. 239), in a report read before the Austra- 

 lian Association for the Advancement of Science, described a species of 

 Sphaeroma boring in a log from the fresh-water portion of the Rewa 

 River, Fiji. He also reports Sphaeroma quoyama Milne-Edwards 

 boring in wood in Sydney harbor, Australia, giving illustrations both 

 of the borer and of its work. Sphaeroma verrucauda White is re- 

 ported from Bay of Islands, New Zealand, "in rotten wood in cavities 

 bored by the Teredo." The work of the Sphaeroma is said to be 

 very destructive to marine timber consisting both of hard and soft 

 wood in Sydney, but its operations are said to be limited to the region 

 between low and high tide levels, though Dr. Teesdale (1914, p. 357) 

 states in his discussion of all marine wood borers, including Sphaeroma, 

 that their operations are carried on "from high tide to many feet 

 below the surface." 



Moll (1914) suggests that since isopod wood borers have frequently 

 been brought to the surface from relatively great depths they cannot 

 be regarded as limited to the shore or to the surface in their oper- 

 ations. Other reports suggest to the writer, however, that of the 

 borers it is Limnoria which probably ranges more widely in depth 

 than does Sphaeroma, but that, as Moll notes, the operations of all 

 these borers may range from the bottom to the surface in any available 

 wood, though their destructive work is the more rapid at the surface 

 because of the added action of wave erosion, as well as because of the 

 greater number of individuals congregating at the surface. 



Finally, Mr. Hedley (1901, p. 240) adds that "this species 

 [Sphaeroma verrucauda] has been observed by Mr. Whittelegge to 

 bore holes in sandstone rock at Mosman's Bay," Sidney Harbor, 

 Australia, and that "Sphaeroma verrucauda has been accredited with 

 a similar habit." Janira, another isopod, is mentioned as always 

 associated with Sphaeroma verrucauda when the latter occurs as a 

 wood borer. Stebbing (1904, p. 21) in commenting upon the occur- 

 rence of Sphaeroma verrucauda White expressed the opinion, how- 

 ever, that it is "not likely to have produced the hollows in sandstone 

 in which it is found." If Sphaeroma verrucauda actually bores at 

 times into wood and at times into sandstone, this species would seem 

 to represent a transition stage in the development of the boring habit, 

 parallel to what may have been a similar transition stage in the 

 independent development of the same habit in an American species, 

 Sphaeroma destructor. 



Stebbing (1904, p. 16) also describes borings of an isopod which 

 he attributed to the species Sphaeroma terebrans Bate from cocoanut 



