Mr. W. Clark on the Muricidse. Ill 



ternal aspect to assist arranj;ement ; the first stalk abroad under 

 false colours, the others are clothed in simple integrity, casting 

 off the garb of phrases which imply fictitious values. 



The generic synonymy appended to the sections will enable 

 the collector to arrange his objects, either in the groups of the 

 Linn^an Murex, or in the pseudo-genera of the moderns. The 

 following seven sections will suffice for our Muricidal indigena. 

 The exotic objects will require a few others. 



Murex et Buccinum, Linnaeus. 



Sectio I. 



Testa conica, subinflata, varicosa, efFasa, spiraliter striata. 

 Apertura ovalis. Columella aspera. Operculum corneum. 



Murex erinaceus, Linnaeus, Lamarck, et auctorum. 



Animal spiral, yellowish white ; mantle very thin ; the branchial 

 fold extends veiy little beyond the canal of the shell. The head 

 is small and compressed ; from its angles the moderately long 

 tentacula spring, and almost coalesce at their bases, from which 

 they run tumid to some distance, accompanied by offsets of more 

 than half their length, on which the eyes are placed externally ; 

 from thence the tentacula taper conically to their extremities. 

 The mouth is a vertical fissure beneath the tentacular veil, and 

 emits the characteristic proboscis. The foot when quiescent is 

 nearly oval, but on the march is truncate in front, throwing off 

 on the right and left small auricular points; it is gently con- 

 stricted medially, and has a blunt rounded termination, canying 

 on the posterior upper surface an elongated red-brown corneous 

 unguiculated operculum. 



Lamarck's commentators say, that between the genera Murex 

 and Purpura there are sufficient marks of distinction, and in 

 support of this opinion they adduce the truncature of the ten- 

 tacula at their offsets in Purpura, which they state is more appa- 

 rent than in Murex. We dissent from these views, and think the 

 distinction is purely ideal — at least it is so in the species of each 

 genus we have examined : the fact is, that when the tentacula are 

 collapsed, the basal two-thirds appear very tumid and broad at 

 the termini of the offsets, but in fully extended action the trun- 

 cature nearly or altogether vanishes and no peculiarity is appa- 

 rent at these points. 



It will be observed below, that the external organs of Murex 

 lapillus, the Purpura of authors, are nearly identical with those 

 of M. erinaceus, and the internal organs of the two are so 

 similar that it would be a repetition to describe them ; the cor- 

 neous opercula scarcely show distinction ; that of this species may 



