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 Doliwm, Tritonium, Aplysia, and the 
acid secretion of Gastrochena 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 menas. It therefore appears to me to 
be just as prudent and useful to bring forward the chemical 
theory in regard to the perforations of Zimnoria and Chelura 
terebrans in wood, of the Pholas 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 
Lichini 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 ania 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 
Leucodore, 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 
tous. Moreover I asked a distinguished young chemist, Dr. 
Crum Brown, to repeat the tests. He wrote me as follows: 
—“T 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- 
* T am glad to say that Mr. Lankester has since seen reason to change 
his opinion. While maintaining the correctness of his statement with 
regard to the acidity of Zewcodore, he withdrew his chemical theory after 
the reading of my paper at the Meeting of the British Association. 
