50 Mr. W. Clark on the lanthinse, Scalarise, 



short, narrow, and bevelled on both sides, arcuated gently in front 

 when on the march, and slightly auricled ; at rest subtioincate ; 

 it is also grooved transversely in front, dividing the sole from 

 the upper part, and forming a distinct labium, the sole being 

 somewhat the longest ; it tapers to a slender rounded termination, 

 carrying at some distance from the extremity, on a simple lobe, 

 a white spiral operculum of three turns ; the two first are very 

 small and eccentric, the third rapidly increases and occupies 

 y^ths of the area, and is marked with elliptical strise of incre- 

 ment ; the posterior half of the foot is deeply grooved longitu- 

 dinally and medially in the sole, with a central depression 

 exactly as in Murex tubercularisy but not quite so decided : — it is 

 probable that this groove, and apparent, if not real, solution of 

 continuity, is not solely to convey water to the foot, but also to 

 assist the folding of that organ on its anterior portion, and the 

 central pit is to aid another doubling at right angles. I wit- 

 nessed the operation both in retraction and when the animal 

 deployed the foot, which confirmed that part of M. Bivona's de- 

 scription, — "Pes, plica triplici in testam retractus." On retrac- 

 tion, each posterior longitudinal half, bounded by the groove, is 

 folded on its counterpart, forming two plications ; then these 

 halves are at the central depression doubled on the anterior 

 portion, and the whole is withdrawn and covered by the oper- 

 culum. Of course the routine of exsertion is exactly the converse, 

 but it appears to me that these manoeuvres are pretty much the 

 same in all the Gasteropoda. Scalaria, in these and other points, 

 is closely allied to Murex tubercularis, as far as external organs are 

 considered ; it only differs in having a spiral operculum instead 

 of a muricidal one. 



This creature is very free in showing its points. It inhabits 

 the three zones. The one described was captured by myself in the 

 middle of the littoral disti-ict, at the roots of the Corallina offici- 

 nalis, at Exmouth, where it is of rare occurrence. I have not 

 taken more than five or six live specimens of this species and 

 the S. communis in thirty years ; most of them were from the 

 coral zone. I observed that when the animal was in extremis, 

 it emitted, like the lanthina, a brilliant purple fluid. I am not 

 prepared to speak, at present, of the reproductive organs and 

 the internal mechanism of the proboscis, but we may safely con- 

 clude that it does not greatly differ from the Buccinum undatum, — 

 Murex with me. I have examined the S. communis, which does 

 not vary in the organs from this species; its colours and dispo- 

 sition of the markings exhibit some differences. 



I believe the only other British species are the S. Trevilliana, 

 S. Grcenlandica, and S. Turtoni. The two first I have not seen 

 alive ; the latter has been examined, but I unfortunately lost the 



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