410 PYRAMIDELLID A. 
Chem. rufa, is acknowledged as a distinct species in the Ap- 
pendix of the ‘ British Mollusca.’ The Chem. Sandvicensis, 
the dolioliformis, nonnull., is an old, well-known, accredited 
species of Walker, Test. Min. Rar. We have observed it for 
the last forty years. 
Nothing is more common than a littoral and coralline zone 
variety of the same species; these, from the effect of lhght, 
air, sun, habitat, and depth of water, are often so strongly 
marked as to induce conchologists to convert them into spe- 
cies, whereas, if they had examined the animal, they would 
have escaped the mortification of retractation. 
Sometimes the littoral shell 1s the larger, and sometimes the 
coralline zone variety. The C. truncatula recently redisco- 
vered by Mr. Barlee, at Plymouth, is large and elongated in 
the deeper zones; but the littoral variety, as with C. pallida, 
is dwarfish, more slender, and is called by recent authors 
C. cylindrica. They are undoubted varieties of each other, 
and both are the Turbo nivosus of Montagu; with me, Chem- 
nitzia nivosa. As proof, the learned authors of the ‘ British 
Mollusca’ have, on the highest authority, pronounced the 
C. cylindrica to be the “ nivosa” of Montagu; it follows, that 
the C. truncatula, which, without question, is the adult of 
C. cylindrica, is also the “nivosa” of Montagu. A careful 
comparison of the opercula of the two has since fully con- 
firmed this view. 
These are the causes that have produced so many spurious 
species ; we need only instance the Chem. pallida of Montagu, 
the parent of the following—Odostomia eulimoides, O. rissoides, 
O. notata, O. albella, O. dubia, O. alba, O. nitida, O. glabrata. 
The discovery of the animal of Mr. Alder’s Chem. obliqua 
enables us to say, that the Chem. diaphana of authors is the 
young of that species. The Chem. Warrenii, called by some 
the decorata of Mr. Bean, is very distinct, both as to animal 
and shell, from the “odliqua”’; and Montagu’s Chem. in- 
sculpta is well distinguished from both, as our account of the 
animals of the three will show. With respect to Mr. Alder’s 
Chem. conspicua and C. striolata, we have stated our opmion 
in the notes on Chem. acuta. 
