Mr. W. Clark on. the Cheumitzi^fc. 389 



specific appellation. I think no other shell will ever be found to 

 represent Mr. Walker's objec^,,,,^. .^i,. ,,.,(,-,„„„, ggjori ariJ a-j^ 



Chemnitzia eulimoides, Hanlcy. 

 Turho pallidus, Montagu et Auot. 



This species is, I think, undoubtedly Montagu's shell. I draw 

 my conclusions from his figure and notes, in the ' Testacea 

 Britannica/ — not from the fragment of what is said to be his type, 

 that still exists, and is enveloped in dubiety, whether it be ge- 

 nuine, spurious, or a substitution by accident. When I stated 

 in the December ' Annals ' for 1850, in the memoir on the Pyra- 

 midellidcB, under the article Chemnitzia eulimoides, that that 

 species, the very common C. pallida of authors, was not the 

 "pallida " of Montagu, I did so, as I had been led to believe that 

 an undoubted type of his species existed to prove that fact; the 

 ' British Mollusca ' has since informed me that is not the case ; 

 I therefore gladly revert to the commonly received opinion, which 

 I have always entertained, that the well-known Chem. pallida of 

 almost ail authors, or one of its innumerable varieties, is the true 

 Moutaguan "pallida." Montagu says his shell is veiy rare, 

 but that arises from the very different appliances of his day 

 and ours for obtaining shells. When he wrote, the minuter 

 species were procured by ocular labour from the littoral sands, 

 and as they were rarely washed u]) from the deeper and more 

 distant zones, they were of course very scarce, but which, if the 

 modern dredge or trawl-boat had been in general use, would 

 have afforded abundance. ' •*"'^' ^" 



We have numerous suites of the C. pallida, our type, of all 

 adult sizes; of all juvenile ones; of all forms, slender, tumid, 

 short, elongated; of every descrii)tion of markings, smooth, rough, 

 spirally ridged, or more finely striated, with the fold sometimes 

 conspicuous, often scarcely visible, and an umbilicus of most 

 variable character : all these phases of the same species may be 

 seen in our cabinet, in which scarcely a specimen of the CheW^. 

 pallida can be matched, because all differ. What has been the 

 result ? Authors have produced their interminable lists of va- 

 rieties; and when a somewhat more differential form was met 

 with, it was promoted to a species. We have not the slightest 

 doubt that the Chemnitzia rissoides is a dwarf littoral variety of 

 the ''jjallida." A comparison of oui- notes on the two animals 

 bears us out in this view ; these two alone agree, whilst every 

 other exhibits some difference. Besides, onr examination of tll6 

 opercula of this genus (see the observations in the April 'Anlials," 

 1851) strongly supports their identity; they are amongst thel^w 

 species thai have the pillar- lip flap moveable, resulting from car- 



