[ 260] 



Hmono the Sea THrcbins^ 



Part II. 

 By George Swainson, F.L.S. 

 Plate XVIII. 



N our last paper we promised to continue the account 

 of the Sea Urchins, with a description of the 

 mouth and digestive system ; but before doing so 

 we must describe our more recent search for living 

 forms of the small Heart Urchin {Echinocarduan 

 cordatiim), of which we described the characters 

 when dead on page 13, under the old name, which 

 Forbes gave it, A7nphidotus cordatus. It is to 

 be met with cast up, dry and brittle, along most 

 sandy beaches, and any naturalist visiting our Lancashire 

 seaside resorts who will follow a high tide out to its lowest 

 recess and dig there will be almost sure to turn up the living 

 forms of this beautiful Urchin, which can be kept alive 

 in a glass jar for a length of time sufficient to study it with 

 interest. There is a large sand-bank opposite the end of St. 

 Anne's pier, which stretches away towards Lytham and Preston, 

 and is very dangerous for navigation. Our readers may perhaps 

 remember the terrible disaster which occurred on this bank nearly 

 four years ago, when the lifeboats belonging to St. Anne's and 

 Southport were both wrecked and their crews drowned in an 

 attempt to rescue the crew of the ship Mexico^ which had struck 

 upon these banks. 



. After crossing over this bank one warm afternoon in May, we 

 commenced digging in one or two likely spots, hoping to find the 

 rare, wormlike Holothurian, Synapta inherens, which, however, has 

 never been recorded as found on these shores. It is well known 

 among microscopists for the beauty of its plates and anchor-like 

 spicules with which its skin is studded. It was, perhaps, a forlorn 

 hope, but we were encouraged to persevere in our search by the 

 fact that on three different occasions during the months of April 

 and May, this year and last, we have taken in our surface-net off 



