CHEMNITZIA. 417 



and as they were rarely washed up from the deeper and more 

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

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

 would have been obtained in 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 description of markings, smooth, 

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

 sometimes conspicuous, often scarcely visible, and an umbi- 

 licus of most variable character : all these phases of the same 

 species may be seen in our cabinet, in which scarcely a 

 specimen of the C. pallida can be matched, because all differ . 

 What has been the result? Authors have produced their 

 interminable lists of varieties ; 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 "pallida" A comparison of 

 our notes on the two animals bears us out in this view ; these 

 two alone agree, whilst every other exhibits some difference. 

 Besides, our examination of the opercula of this genus 

 strongly supports their identity; they are amongst the few 

 species that have the pillar-lip flap moveable, resulting from 

 cartilaginous flexibility. This rissoidean variety of Chem. 

 pallida is the parent of the C. albella and C. dubia of au- 

 thors. We possess them both, besides having had authentic 

 specimens sent to us by Mr. Barlee for inspection ; the C. alba 

 and C. nitida, from the figures in the ' British Mollusca/ and 

 in other works, are, beyond doubt, of the same parentage. 

 I engage to match any of the four species I have named. I 

 conclude, from the ( British Mollusca/ that the C. notata, non- 

 null, is a variety of the typical "pallida" Montagu's shell, 

 from his figure, is also probably a semistriated "pallida;" one of 

 the varieties with a retired inconspicuous fold, and a produced 

 spire, smooth or polished by attrition. We have here a goodly 

 progeny of, as I believe, six pseudo-species from a single 

 parent : I must be allowed to insist on this position with 

 respect to C. pallida and its spurious offspring. I think it 

 cannot be subverted. 



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