386 JOURNAL OF CONCHOLOGV. 



MIMICRY IN MOLLUSCA. 

 By EDGAR LEOPOLD LAYARD, C.M.G., F.Z.S., etc. 



(Read before the Conchological Society, Februarj' 15th, 1894 



I read with much interest the Presidential address by Mr. 

 P. B. Mason, and while doing so, one or two little things oc- 

 curred to me that I think are of interest. All my life I have 

 been a 'collector' and my work has lain in the woods and fields, 

 to my great delight and happiness, and now when old age and 

 ill-health confine me to the house, I have the pleasures of remi- 

 niscence and my collection of shells. 



Our President remarks that we ' do not know that any case 

 (*f mimicry has lieen brought forward among the moUusca.' Is 

 not TrocJuis agglutinans a case of mimicry for ' protection,' as 

 the President terms it ? If not, why does the creature fasten 

 bits of shells and stones to its covering ? I dredged it abundantly 

 at Point Pedro, in the north of Ceylon, and always on ground 

 covered with materials similar to those placed on its shell. 

 Indeed, it was difficult to distinguish the shells from the rubbish 

 in the dredge. I have known examples of this shell found in 

 large fish. Can the attaching of this extraneous matter, by 

 rendering them so similar to their surroundings, save them from 

 being devoured ? 



In 1854, I was in the Comoro Islands, off the east coast 

 of Africa. One day I took refuge under a bushy tree creeper 

 from a shower of rain. I observed that the branches were 

 covered with short stout spines. As the rain ran down the 

 branches I was astonished to see some of the ' spines ' move 

 along the bark ! On taking them in my hand was pleased to 

 find that they were Bulimini ! They were covered with a 

 thick, scurfy epidermis, exactly like the spines of the creeper, 

 from which I could not distinguish them, until I had touched 

 them. When cleaned from the epidermis, they were clear shining 

 brown, I have some still in my cabinet. I suppose our 

 President knows the beautiful Bulimus iniltocheilns Reeve, from 



J. C.,- vii. , July 1894. 



