Mr. W. Clark on the Muricidse. 115 



Having taken the bold step to merge one of the classic 

 genera of Linnaeus and authors in the genus Murex, I must 

 say a few words by way of justification^ in addition to what 

 I have advanced on this point in the former part of the present 

 memoir. I am prepared to have much obloquy heaped on 

 me for my presumption ; I shall enter on no defence beyond 

 the present observations, but will leave to the unerring critic 

 Time to pass sentence on the step I have taken. I will now 

 only observe, that I have as much right to suppress, on what 

 I consider to be just grounds, a Linnsean genus, as others 

 have to split one into twenty genera; and I am confident 

 that if the great and candid Linnaeus had known as much of the 

 animals of the Murices and Buccina as the progress of science 

 has made known, he would have merged one or the other of 

 these genera : no conscientious naturalist can support both with 

 identical animals as regards all essentials. I have preferred to 

 retain Murex as the representative of the most extensive group, 

 and by far the elder genus. The British Murices of this group 

 are very few ; we have only examined the M. undatus : the animal 

 of M. ovum, if indigenous, has not occurred, nor that of the 

 Buccinum acuminatum of authors. 



Murex et Buccinum, Linnaeus et nobis. 

 Sectio IV. 



Testa tumida, Isevis, ssepe spiraliter substriata. Canalis ob- 

 liquo-dorsali-brevissimus. Apertura ovalis. Columella dorso- 

 fastigiata. Operculum corneum. 



Murex lapillus, nonnuU et nobis. 



Buccinum lapillus, Montagu. 

 Purpura lapillus, Lamarck et aliorum. 



Animal spiral, of a uniform pure white or pale yellow, without 

 the intermixture of other colours and markings, except a single 

 superficial fine longitudinal line of intenser hue which divides 

 the under part of the foot in two portions ; the mantle is of very 

 thin texture, lining the shell only to the margin, except the part 

 constituting the branchial fold, which is carried occasionally in 

 marching a little beyond the short canal. The head is very small, 

 slender and flat, from which spring the moderately long ten- 

 tacula that are tumid and rounded from their bases, accompanied 

 for two-thirds of the length by offsets on which the eyes are 

 placed externally, and from thence they run conically to not 

 very pointed terminations ; the mouth and its vertical fissure is 

 beneath, from which a short proboscis is very rarely seen pro- 

 truded. The foot at rest is nearly an oval, but in action is trun- 



8* 



