56 SUPPLEMENT TO THE CRAG MOLLUSCA. 



Alvania albella, Leach, M.S. Crag Moll., vol. i, p. 99. Tab. XII, fig. lie. 



Alvania albella, S. Wood. Annals and Mag. of Nat. Hist., vol. ix, p. 534, 1842. 

 Aclis Walleri, Jeffreys. Brit. Conch., vol. iv, p. 105, pi. lxxii, fig. 4, 1867. 



Locality. Cor. Crag, Sutton. 



This species was given by me in my catalogue in the ' Annals and Mag. of Nat. 

 Hist.,' for 1842, under the name albella, a manuscript name of Dr. Leach for the 

 recent shell since called Walleri, which, as stated at p. 99 of the ' Crag Moll.,' I found on 

 a tablet in the Brit. Museum, with the name in Dr. Leach's handwriting attached. This 

 tablet, I regret to say, cannot now be found, and some confusion has arisen in conse- 

 quence, as Mr. Jeffreys appears to think ('Brit. Cone.,' vol. iv, p. 104) that albella of 

 Leach was ascaris of Turt. Mr. Jeffreys recognises Walleri in a single specimen in my 

 collection in the British Museum, but there are twenty-six specimens there on a separate 

 tablet which appear to me identical in all respects with some specimens of his recent Walleri 

 which he kindly gave me. I fell into the mistake in the ' Crag Moll.' of supposing this 

 to be an eroded form of the shell there described as ascaris {supranitida), but I have now 

 reverted to my more correct views of 1842. Since my collection went to the British 

 Museum, both this shell and supranitida have become extremely rare in the Crag. 



Some Conchologists have adopted the name of Aclis for this genus, and it may 

 require a remark from me in explanation for not following the same plan. In the 

 first place I used the name of Alvania in 1842, when the Crag shell was fully described, 

 and this was previous to the name of Aclis, proposed by Dr. Loven in 1846. In the 

 second place I merely employed a name that had been given by Leach, and attached by 

 him to a specimen in the Brit. Mus. ; and in the third place the shells included under the 

 name of Alvania, by Weinkauff and others, have no characters by which they could be 

 distinguished genetically from those called Bissoa. 



MENESTHO, Mailer, 1842. 



Diagn. Gen. " Animal pede elongato, angusto, ore simplici, membrana linguali 

 destitulo ; tentaculis brevioribus, crassiusculis, oculos perparvos ad basin internum fere ntibus. 

 Operculo pauco-spirato. Testa conica turrita.'' — [Moll.) 



The above is a description of this proposed genus, and the author has referred to 

 Turbo albulus of the Fauna Greenlandica, as his intended type, the shell of which presents a 

 different form of aperture from either Bissoa or Turritella, and approaches nearest to 

 Pasithea, Lea. ; but we do not know the species intended as the type of this latter genus 

 in which several very different forms have been included. 



