542 Rev. L. Guilding on the Zoology of 



Ostrea Rhizophora. 



O. flavescens, pallii marginibus tentaculisque brunneis : bran- 

 chiis inferne lividis: appendiculis labialibus latis, acuminatis. 



Testa elongata, ovata, apice acutissimo ; valva inferiori convexa, 

 solida, saepe arcuata ; umbonis alis saepe foliaceo - expansis, 

 plicatis; !amellis irregularibus, imbricatis, rarp fornicatis. 



Desc. Color pallidas, vel flavescenti-candidus, striis longi- 

 tudinalibus irregularibus purpureis vel ferrugineo-flavis. Valvae 

 intus purpureo nebulosae, submargaritaceae. 



It adheres in vast numbers to the roots of the mangrove trees, 

 (Rhizojiliora Mangle^) which grow on the margins of the 

 Lagoons of Carriacou, an island in the neighbouring government 

 of Grenada; from which it is taken up in company with the 

 Perna Ephippium, Mi/tili, Serpulce, and Cirrhipedes. 



It is known by the name of the Mangrove oyster, and is 

 highly esteemed for the table, extending to innumerable varieties, 

 both as to figure and colouring. They adhere in large clusters 

 both to the bark of the Mangrove roots and to neighbouring 

 shells. The cavity is often disfigured with calcareous blackened 

 blisters, which are laid by the pallium over any extraneous 

 bodies which happen to intrude within the shell. 



Fam. Pernad^. Guild. 

 Gen. Perna. Lam., Sow., De Blainv. 

 Ostrea. Linn. 



Char. Gen. 



Animal. Corpus compressum : vertex sub-tentaculatus : ab- 

 domen arcuatum, byssiferum. Pallium liberum, retractile ; pos- 

 tice in duas paginas aequales, latissimas, liberas, ad marginena 

 serie duplici tentaculatas divisum : branchiarum fimbrim qua- 

 tuor, aequales, parallelae, inferne inter pallii paginas positae ; 

 brachium elongatum canaliculatum, ad basin byssi maximi multi- 

 filati. Musculus adductorius bilobatus ; lobo hoc minori ovatOj 

 illo lunato-elongato. 



