DUBUH FATU&AL HI8T0BT SOCIETr. 139 



Those holes are generally excayated by Hiatella rugosa, specimens of which are 

 here presented. I should say that in the majoritv of cases this is the mollose 

 which will be found on breaking^ up those stones ; but there are other and rarer 

 shells to be found, which I shall now bring under your notice, and which I pro> 

 cured in my immediate vicinity, thrown on the beach. The first is Venenipis 

 irus. Old and obsolete fraements of this shell were found by me in breaking up 

 some of those boulders, and I placed them on a card, which I hold in my hand, 

 and notice them as the first inaication of this desideratum. Encouraged by this 

 gleam, I laid on my blows with a heart and a hand, and was rewarded by obtain- 

 ing those fine specimens. It may be in the recollection of some of the Members 

 present that I noticed the fact of baring obtained this shell in my paper on the 

 shells of Bertirbie Bay, but under very different circumstances. There the 

 shores are bounded by granitic rocks ; not a particle of limestone is to be found ; 

 how the germ of the mollusc was preservea, and how the animal, arriving at 

 maturity, could maintain its life and position, is a matter of high interest. Into 

 the rock the animal could not enter ; if it were there, it would be safe, but it 

 would be certain destruction if it were free, and subject to the currents. 

 •• Fixity of tenure" seems to be essential for the preservation of bivalves. This 

 end was attained by the animal being provided with a byssus of great strength, 

 by which it attached itself to the rock, which held it so firmly that it was with 

 difiiculty my poor and talented friend M'Calla could detach it. What wonderful 



EroviRlons are accorded by the great Creator for the preservation of the hum- 

 lest of his creatures 1 In company with Venerupis irus I found Gastrocheena 

 pholadia. This mollusc affords another wondrous example of the power of adap- 

 tation, so as to insure preservation in almost any position it may be placed in. 

 Here 1 found it burrowing in hard crystalline limestone. On the other hand, I 

 found it in Berterbie Bay in its more elaborate form, an account of which I had 

 the honour of laying before the Society in the paper I read on the Shells of that 

 Bay in December, 1844. That Bay is surrounded, as I said before, by granitic 

 rocks; there is a total absence of limestone. We have seen how the animal of 

 Venerupis irus sustained itself in the midst of such a difiiculty. Let us now ex- 

 amine how this tender Gastrochaena not only protects itself, but lives safely, 

 until its privacy is intruded on by the sharp edge of a dredge. 1 have herei a 

 beautiful exemplification. The animal, when in its free state, selects (there is no 

 chance) a suitable situation for its domicile, generally the obsolete valve of Lu- 

 traria or Pectunculus pilosus; it immediately agglutinates the siliceous particles 

 which lie immediately about it, moulds them into the form of an exquisite dome, 

 and thus effectually and permanently protects itself. But this process would 

 prove fatal to the animal, as completely shutting out the water — how does it 

 obviate this difficulty ? It augers or bores a hole through the shell, on which it 

 rests, immediately under the dome; but this would rather expose it to danger; 

 at least it would very imperfectly protect it from the intrusion of what might 

 prove hurtful to it. What further steps are taken to rectify this difficulty ? It 

 erects immediately over the hole a calcareous tube, broad at the base and taper- 

 ing towards the top ; its fleshy tube accurately fills this, and thus the entrance 

 is effectually closed against any hurtful substance or hostile animal. Thus pro- 

 tected, it has nothing to fear ; it is completely cased in a coat of mail, and at the 

 same time a free communication with the water is maintained. I have thus given 

 a hasty sketch of this highly interesting mollusc. It may be considered only a 

 repetition of what was said before; but, independently ot the interest attached 

 to the subject, I have a personal motive in thus noticing it again ; and it appears 

 te me that the Society has also an interest in the matter — for I cannot conceal 

 the fact, that the moment a paper, whether good or bad, is read before this body, 

 it ceases to be the property of the author, and becomes that of the Society ; and 

 this, in my mind, should prove a most cogent reason for publishing the Trans- 

 actions of the Society, unless it is determined still to permit the credit of any 

 discovery in natural history, made b^any of its Members, and communicated to 

 it, to be torn from it. I shall explain the reason of my offering those observa- 



