Mr. W. Glark o/i the Chemnitzise. 387 



it is with some hesitation they have followed the suggestions of 

 theii* friends ; and well they might pause, as they have described 

 an entirely distinct species, a northern one, the Chemnitsia fulvo- 

 cincta of Thompson and Alder, for the true rufa, which we found 

 thirty years ago at Exmouth, and took five in 1850, which sup- 

 plied the notes of our memoir. The description of the animal in 

 the *■ British Mollusca ' refers to the C. fulvocincta, and appears 

 to differ from ours of the true " inifa," in those slight specialties 

 which might be expected in such congeneric creatures : it is really 

 t(xtraordiuary how two species so totally different, as to the hard 

 parts, should have been confounded. I will now state the cha- 

 racters of each. 



The C. fulvocincta is well figured in the 'British Mollusca' 

 under the title of C. rufa ; it is more conical and tapers more 

 rapidly than the true C. rufa ; it has rarely more than eleven or 

 twelve volutions, and sixteen to eighteen ribs, somewhat raised 

 and sinuated ; each volution slopes from its base to the ascending 

 suture, which is merely a fine line ; it is very glossy, with a most 

 conspicuous yellow or orange band spirally coasting the five or 

 six last turns ; the basal portion of the aperture is subrotund. 



The genuine C. rufa is generally larger, though it has some 

 very slender varieties, one of which is figured in the ' British 

 Mollusca ' under the appellation of C. formosa, that most accu- 

 rately represents our true Exmouth shells of the ' rufa/ in which, 

 in perfect specimens, there are often fourteen volutions and twenty 

 ribs on the body ; they are plain, straight, and not raised ; the 

 suture, instead of a fine line, is decidedly grooved ; the inter- 

 stitial striae are adequately developed ; the basal periphery of the 

 aperture is usually less rounded and more subquadrangular, and 

 the base of the body-whorl exhibits greater tumidity than in the 

 C. fulvocincta. Our beautiful and perfect specimens are not 

 glabrous ; on the contrary they show a palish dull rufous colour, 

 with not a trace of the conspicuous tawny orange spiral fascia of 

 its congener : in fact the true " rufa " differs in every point from 

 the "fulvocincta." This comparison obhges me, with every de- 

 ference, to submit, that for the Chemnitzia rufa of the ' British 

 Mollusca,' the C. fulvocincta be substituted, and the southern 

 shell they have alluded to be named C. rufa, as it and the Ex- 

 mouth examples truly represent that species, adopting their 

 C formosa as a slender variety and synonym ; indeed its figure 

 excellently represents the " rufa." 



The C. rufescens is decidedly distinct from either the " rufa " 

 or "fulvocincta" as well as from the C scalaris, which I obtained 

 at Exmouth twenty-five years ago, and have met with several 

 specimens at the same place in 1850, but not alive.'* 'JtiJ ifiniBJ 



