292 Dr. W. C. M'Intosh on the Boring of certain Annelids. 



a free state, and in such a quantity as to act on calcareous 

 rock or shell, is a likely accompaniment to such an animal as 

 Leucodore working in a tube, whatever may be the case with 

 the salivary glands of Dolium^ Tritonium^ Aplysia^ and the 

 acid secretion of Gastrochoena and other Mollusca. Annelids 

 are very sensitive to irritants and narcotics, and must be 

 judged by the same rules in this respect as the majority of 

 other animals. And this statement is not impugned by the 

 fact that a few, such as Cirratulus^ may occasionally be 

 found burrowing in odoriferous mud, like the ubiquitous 

 crustacean Carcinus mcenas. It therefore appears to me to 

 be just as prudent and useful to bring forward the chemical 

 theory in regard to the perforations of Limnoria and Ghelura 

 terebrans in wood, of the Phohis crispata in the hard shale 

 and sandstone in company with Leucodore at St. Andrews, 

 in regard to the deep cavities made by Patella vulgata in the 

 latter rock on the same sites, in regard to the borings of the 

 Echini and the wide interlacing channels of Hymeniacidon 

 in shells and stones on all our shores, as to produce it for the 

 explanation of Annelidan perforations. Yet Mr. Lankester 

 prefaced his observations on the boring of Leucodore by the 

 statement that he was prepared to find such due to chemical 

 action, because an acid reaction was found in Sabella saxi- 

 cava^. We are thus prepared for the following remark : — 

 " Supposing, then, the agency in Leucodore to be a chemical 

 one, has any acid been observed ? It has : specimens of 

 LeucodorCj placed on litmus-paper, give a strong acid re- 

 action." I have carefully tested for acidity in numerous 

 specimens of Leucodore from St. Andrews ; but not a trace 

 thereof rewarded my attempts, though ' an ambiguous stain is 

 occasionally produced by old sea-water in which they and 

 other Annelids have been confined. No acid reaction at all 

 was visible ; and to apply the epithet ^' strong" to such a case 

 would certainly be after the fashion of a chemistry unknown 

 to us. Moreover I asked a distinguished young chemist. Dr. 

 Crum Brown, to repeat the tests. He wrote me as follows : 

 — " I found exactly as you have stated on the labels, viz. 

 that Cephalothrix filiformis has a marked acid reaction in 

 every part of its body, and that Leucodore ciliata is quite 

 neutral. The perforated and grooved stone is not calcareous, 

 and is scarcely attacked by acids : prolonged action of tole- 

 rably strong hydrochloric acid dissolves a little iron. ... It 

 appears to be a kind of mica schist." I was not more suc- 



* I am glad to say that Mr. Lankester has since seen reason to change 

 liis opinion. While maintaining the correctness of his statement with 

 regard to the acidity of Leucodore^ he withdrew his chemical theory after 

 the reading of my paper at the Meeting of the British Association. 



