Microscopical Society of Victoria. 
21 
<0n the Radula or Lingual Ribbon of Australian Mollusca, 
By the Rev. J. E. Tenison-Woods, F.L.S., F.G.S., &e. 
[Bead 29th May, 1879.] 
It will be readily conceded that there is no subject 
which more legitimately belongs to a microscopical society 
than investigations on the radula or lingual ribbon of 
mollusca. I may add that there is hardly any other 
subject where so much is to be done, or where such important 
results may be expected as this one in Australia, It is, 
I may say, a clear field, and quite, or almost quite, an 
untrodden one. I cannot call to mind any special 
publication on the subject except an article in a popular 
science serial some years ago. In this there were no 
Dames of the species from which the radulas had been taken, 
as the writer did not know them. The scientific value of the 
contribution was thus lost. I do not know of any other 
published memoir especially devoted to this subject. In the 
course of my own. small investigations on the habits and 
economy of Australian mollusca, 1 have necessarily met with 
many curious facts connected with the radula Some I have 
published, as in an article on some Tasmanian PatelUdce , 
published in the " Proceedings of the Royal Society of 
Tasmania/' in 1870, p. 43. A few others I have kept by 
me as notes, which I shall endeavour to embody in this 
paper. My object is rather to review the subject, with 
a view to excite interest and encourage investigation, 
because I do not suppose that the very small contribution 
I can make to knowledge in this respect would otherwise be 
worthy the attention of this Society, or a place in its records 
The lingual dentition of mollusca has lately taken a 
large place in attempts made to review the classification 
of this sub-kingdom. The “ Genera of Recent Mollusca,” 
by Messrs. H. and A Adams, was one of the first works 
that dealt with the matter systematically. In nearly all 
their descriptions they refer to the presence or absence 
of the radula, and the mode of dentition. They point 
out in their introduction, that the radula is a membrane 
covered with hooks or prickles, which are usually arranged 
differently in different families. It commonly forms a 
triple band, of which the central part is termed by them 
the rachis, and the lateral parts pleura. The teeth on 
the middle part are termed central; those on the pleura 
