Mr. E. R. Lankester on Lithodomous Annelids. 235 
the clay is a septarian nodule (carbonate of lime); and this 
resents the characteristic keyhole apertures and double gal- 
Tice which the Leuwcodore makes in the chalk and limestone 
boulders of the Isle of Wight. 
These two cases of the boring of stones by Annelids are the 
only ones which at present have come under my notice. The 
case of Sabella saxicava is described by De Quatrefages ; but of 
the boring of Leucodore [have seen no clear description or figure. 
Thousands of persons and hundreds of naturalists must have 
seen these borings; yet none have given more than a brief 
allusion to the matter. M. de Quatrefages alludes to the fact 
in a general way in speaking of the family of “‘ Leucodoriens:”’ 
he says, “‘Some species evidently bore very hard calcareous 
rocks,’ and mentions fragments of rock “entirely worm-eaten.”’ 
Mr. Templeton, in a paper on various marine animals, pub- 
lished in London’s Magazine in 1837, has given the most de- 
finite allusion to the boring of Leucodore. He gives a rough 
outline figure of the gallery, without describing its form, and 
speaks of the worm as Spio calcarea: the Spio of Fabricius 
was very probably a ‘‘ Leucodorien.”” Mr. Spence Bate, in a 
paper on marine boring animals, alludes to certain Annelids, 
by which he may very possibly mean to indicate both Sabella 
and Leucodore. Mr. Gwyn Jetireys also alludes to borings by 
Annelids in the same anonymous manner. The most remark- 
able allusion, however, to lithodomous Annelids, and one 
which shows how very indefinite the knowledge of this matter 
has been, is that of Dr. Bowerbank, quoted by Mr. Albany 
Hancock in his recent paper on Cliona. Dr. Bowerbank at- 
tributes the passages in shells which are inhabited by Cliona 
to a “lithodomous Annelid.” He does not venture to say that 
he has seen this animal, but speaks of it as a very likely being 
to play such a part. Mr. Hancock, in replying to this, did 
not adduce the most complete refutation of this theory (viz. 
that no such lithodomous Annelid was known), but urged that 
the form of the passages was not such as an Annelid would be 
likely to produce. The two above-described cases of perfora- 
tion are, I believe, the only ones at present observed; and 
certainly, in both, the form of the perforation is very unlike that 
of any Cliona. — 
2. Having thus described what is the form of the perfora- 
tions made by the two lithodomous Annelids, the question 
arises as to how these perforations are made, and in what way, 
if any, the structure of the worm is related to such a habit. 
With regard to Sabella saxicava, in the first place, there is no 
hard structure in this species which is not possessed by other 
non-lithodomous species; and no one can maintain that the 
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