Mr. E. R. Lankester on Lithodomous Annelids. 235 



the clay is a septarian nodule (carbonate of lime) ; and this 

 presents the characteristic keyhole apertures and double gal- 

 leries which the Leucodore 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 oi Leucodore I have seen no clear description or figure. 

 Thousands of persons and hundi-eds 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 Loudon's Magazine in 1837, has given the most de- 

 finite allusion to the boring of Leucodore. He gives a rough 

 outline figm-e of the gallery, without describing its form, and 

 speaks of the worm as Sjno ccdcarea : the Bpio of Fabricius 

 was very j)robably 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 Jeffreys also alludes to borings by 

 Annelids in the same anonymous manner. The most remark- 

 able allusion, however, to lithodomous Annehds, 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 Avould 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 milike 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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