124 RECORDS OF THE AUSTRALIAN MUSEUM. 



organisms, notwithstanding Duncan's remark that " whilst recog- 

 nising two or three forms of parasitic Algse within these scleren- 

 chymatous structures of recent and ancient date, it does not follow 

 that they are to be made into different species. They may all be 

 parts of the same mycelium-like growth of the parasite, and may 

 depend upon the nature of the nidus in which growth has taken 

 place."* In this opinion I am supported by that of my colleague, 

 Mr. Thomas Whitelegge, who has had great experience in the 

 microscopic examination of Cryptogamic life. 



Tubes similar to both those now under description have been 

 investigated by many Biologists, witli the result of much difference 

 of opinion as to their nature. Prof. John Quekett appears to 

 have been one of the first to investigate similar chains of monili- 

 form cells, and gave an excellent illustration! of them permeating 

 the tissues of a coral, at the same time terming them "confervoid 

 growths." He remarked that "confervoid growths also are very 

 frequently met with in the skeletons of corals, as all these bodies 

 possess animal matter, which, decomposing after death, become a 

 nidus for the development of conferva?." In addition to a coral, 

 he figured similar chains permeating the plates of a Chiton,X 

 " large canals running through the entire thickness of the sections 

 sometimes preventing the moniliform appearance represented at 

 B " (his fig. 199). 



Fuller observations seem to have been made on the simpler 

 tubes, whether of a straight or tortuous nature. Drs. Bowerbank 

 and Carpenter contemporaneously conducted examinations of 

 those permeating the hard parts of Mollusca, and both at 

 first clearly misunderstood their nature. Bowerbank referred 

 to these tubes as " Haversian canals," and speaking of them in 

 the shell of Ostrea remarked, "sometimes they pursue their course 

 through this tissue in nearly a straight line for a considerable 

 distance without branching or anastomosing, while in other parts 

 they are tortuous, frequently anastomose, and throw off branches, 

 which have cjecoid terminations. "§ 



In the years 1844 and 1847 Dr. W. B. Carpenter examined 

 tubular perforations in the tests of Mollusca. He referred to 

 simple tubes, more or less regularly disposed, and clo.sely resembling 

 those of an ordinary mycelium. In his first Report he said,j| "The 

 direction and distribution of these tubes are extremely various in 

 different shells ; in general they exist in considerable numbers, 



* Quart. Journ. Geol. Soc, xxxii., 1876, p. 209. 

 t Lectures on Histology, ii., 18.54, p. 153, fig. 78. 

 X Ibid., p. 323, fig. 199 B. 



§ Trans. Micro. Soc. i., 1844, p. 139, pi. xvi., fig. 5. 

 II On the Microscopic Structure of Shells.— -Brit. Assoc. Report, 1844 

 (1845), p. 13. 



