416 PYRAMIDELLID^:. 



scription of the same object : this remark is applicable to all 

 the Chemnitzia. The tentacula are short, flattened, triangular, 

 not pointed, and bevelled like an awl, setaceous, and in some 

 animals suffused with sulphur-yellow ; each has also a longi- 

 tudinal line running between the bevels ; the eyes are at the 

 internal points of the basally-coalescing tentacula, immersed 

 in the skin. The operculigerous lobe is inconspicuous, almost 

 obsolete, with scarcely a trace of lateral extensions. 



In this species the minute branchial plume was found in 

 the usual position, attached to the neck and mantle ; no head- 

 lappets, with scarcely the rudiments of a veil ; the anal pellets 

 were observed to be ejected from the right side; the male 

 organe generateur was not seen. This species scarcely differs 

 from C. acuta : the variation is in colour, and in the anterior 

 part of the foot being less hollowed out. 



There are five or six varieties slightly differing in con- 

 tour. Their principal habitat is at the back of the auricles 

 of the Pecten opercularis of the coralline zone, where they 

 may be seen in clusters of six to ten, imbedded in animal 

 mucus. 



This is a very common species, and 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 genuine, spurious, or a substitution 

 by accident. When I stated in the December ' Annals' for 

 1850, in the memoir on the Pyramidellida, under the article 

 Chemnitzia eulimoides, that that species, the very common 

 C. pallida of authors, was not the "pallida " of Montagu, I 

 did so, from having been led to believe that an undoubted 

 type of his species existed to prove that fact ; the ' British 

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

 I therefore gladly revert to the commonly received opinion, 

 which I had previously entertained, that the well-known Chem. 

 pallida of almost all authors, or one of its innumerable varie- 

 ties, is the true Montaguan "pallida" Montagu has stated 

 his "pallida " to be very rare. When he wrote, the minuter 

 species were procured by ocular labour from the littoral sands, 



