404 Prof. T. C. Archer on a Species of Ostrea. 



name of S. auriculafolia. The plant so named in his ' Cat. des 

 PI. des Pyrenees' is referred by all the French botanists to the 

 S. lychnidifolia (Gir.); but surely Mr. Bcntham would not com- 

 bine our plants with it ! That would be a union more re- 

 markable even than many of the other conjunctions of species 

 which he expects us to accept upon his authority alone. 



XLIV. On a Species o/Ostrea taken from the copper sheathing on 

 the bottom of a vessel in the Liverpool Graving Docks. By T. C. 

 ARCHER, Professor of Botany in Queen's College, Liverpool. 



THE great rarity of the occurrence of bivalve shells growing upon 

 the bottoms of ships is well known to those who are engaged in 

 the repairs of vessels ; two such instances, however, have occurred 

 in this port, within a few weeks of each other. In the first case, 

 which did not fall under my own notice, the copper sheathing of a 

 vessel from Bombay was found to have attached to it a consider- 

 able number of full-grown shells of a species closely allied to 

 Ostrea edulis. In the second instance, I happened to pass one of 

 our graving docks in which some vessels were undergoing repairs, 

 and was much struck with the immense number of oyster-shells 

 adhering to the bottom of one of them. Upon descending for the 

 purpose of a closer inspection, I found one or two old ship-carpen- 

 ters examining them with great curiosity ; and they informed me 

 that, although they had worked in the Graving Docks from their 

 boyhood, they had never seen oysters on a ship's bottom before. 

 I removed a few of the shells, which thickly covered the greater 

 part of the copper, being thickest near the keel, and took them 

 away for examination. On my return home, I saw at once that 

 it was a species with which I was not familiar, and upon referring 

 to the beautiful and extensive collection in the Liverpool Royal 

 Institution, I found no specimen of the species there ; nor have I 

 been able by reference to local and distant friends to ascertain 

 its name. I therefore hastened to secure a considerable number 

 of specimens for distribution and was only just in time, for they 

 were being rapidly removed and carted away : upwards of a ton 

 and a half were supposed to have been taken from the ship's 

 bottom. 



Deeply imbedded in the interstices of the clumps of oysters, 

 I discovered some small shells attached by a byssus; these are 

 a species of Perna, which Mr. S. P. Woodward obligingly informs 

 me is known to him as a South Sea species. This is of value, 

 as indicating the probable habitat of the Ostrea, otherwise a 

 difficult matter, for very little is known of the antecedents of the 

 vessel, she having been taken as a prize during the Russian war, 



