396 ESCIIARIDjE. 



GEOGRAPHICAL DISTRIBUTION. Mediterranean, 390 fa- 

 thoms (' Porcupine' Exped.) : Bay of Naples (Waters). 

 RANGE IN TIME. Italian Pliocene beds (Manzoni). 



This species is very distinct, from either R. Beaniana or 

 R. cellulosa, Smitt. It seems to be a southern form : all 

 my specimens are from Cornwall; and it is not included 

 amongst Smitt's Scandinavian Polyzoa. The very much 

 produced and recurved rostrum, with its minute, terminal 

 avicularium, and the wing-like elevation of the peristome 

 on one side of it, are the most salient features. These 

 characters distinguish it from both the forms just men- 

 tioned ; and it is further separated from them by differences 

 in the avicularia and fenestrae. 



The surface of the zoarium in R. Couchii is rendered 

 hispid by the immense number of tall, projecting rostra. 

 The avicularia which they support are very minute, as 

 compared with the oral avicularium of R. Beaniana, and 

 are destitute of the denticles. 



The marginal spines seem to be only present on the 

 youngest cells and colonies ; in fully developed specimens 

 they are, as far as I have seen, uniformly absent. The 

 small oval or subcircular avicularia are scarcely present, 

 if at all, on the front surface of the zoarium; they are 

 replaced by the tongue-shaped appendages. 



It is impossible to identify R. reticulata of the ' Cornish 

 Fauna ' by the description there given of it ; and the 

 synonymy is any thing but a trustworthy guide. At the 

 time of the publication of the ( Fauna/ its author had 

 not been able to obtain a Cornish specimen of it; and 

 it holds a place in his work because it had been found in 

 Scilly by Borlase. Many years after, however, I received 

 from Mr. Couch himself a specimen of a Retepora which 

 he had dredged off the Land's End, and which proved to 



