3^ 



ON THE OCCURRENCE OF CREPIDULA 

 FORNICATA, L., OFF THE COAST OF 

 ESSEX. 



By WALTER CROUCH, F.Z.S. {Vice-President). 

 [Ri-ad, 24th February, /i?9y.] 



^ jF the family CalyptrcTeidce, so far as I am aware, only one genus 

 and species has hitherto been recorded as occurring in Great 

 Britain ; /. i?., Calyptrcea sinensis, of Linnaeus. This marine mollusc 

 is, I believe, mainly confined to the Southern coast and Channel 

 Islands. I have taken live specimens off the coast of South Devon, 

 and also near Weymouth, Dorset, where it is fairly common, and 

 generally found attached to stones. 



On the 6lh of September, 1891, when staying at Brightlingsea, 

 in Essex, I ferried over one morning to Stone Point, St. Osyth, there 

 awaiting some friends who were staying at East Mersea, and had 

 agreed to bring the boat over to the " hard" to fetch me ; but the 

 sea was very rough, rolling in from the German Ocean with a S.W. 

 wind, making the estuary of the Rivers Colne and Blackwater 

 choppy and dangerous. They dared not venture, nor would any 

 boatman take me af^ross, so I turned my attention to the shore and 

 surroundings. The previous day I had found Paludestrina venfrosa 

 by the thousand in the brackish water of the ditch of the Martello 

 Tower on the Point. 



In getting marine species I was not very successful, but I took a 

 quantity of Truncatella truncatnla, Lacuna crassior, and a few 

 Anoniia ephippium. The former were all on the underside of large 

 stones, and had never before been recorded in Essex. 



My surprise was great when on turning over a broken bit of 

 oyster-shell (not a native), on the Zosiera which abounds here and 

 is rolled in like ropes by the sea, to find attached a dead shell of 

 Crepidula fornicata, a shell common on the east coast of North 

 Anierica. I remained searching for a long time, picking up and 

 examining every bit of oyster-shell I could see, but could not find 

 another. 



From later inquiries I ascertained that at some time young 

 American oysters had been laid down here to fatten, but whether 

 from the east or west coast I could not discover. That fact, how- 

 ever, sufficiently accounted for a non-European shell being found 

 there, and I concluded that it had been brought over attached to the 

 oyster. I was aware that French and Portuguese oysters had often 



