GASTEROPODA. 31 



named I must leave for further observation and more specimens to determine. It much 

 resembles a small form of Natica helicoides {Islandica, Gmel.), ' Crag Moll./ vol. i, 

 p. 145, tab. xvi, fig. 3, and may possibly be the young of that shell, though it seems to 

 be more elongated, and to possess a more elevated spire and more pointed umbo ; the 

 present specimen is quite free from striae of any kind, and it does not appear to have 

 lost any of its outer coating, which is so common in specimens of Natica from that 

 locality, and this is perhaps in favour of its being distinct. I have not been able to see 

 the living shell to which Mr. Bell has referred it, which, on the label appended to our 

 present specimen, is called " undescribed." The volutions in this specimen are convex, 

 and between them is a deep and depressed suture, like that upon helicoides, but our 

 present shell has a very distinct umbilicus. Mr. Bell tells me he has seen the young of 

 N. helicoides, and that our present shell differs from it. I have put a mark of doubt 

 against the present name, as I have not much confidence in the above assignment. 



Natica Groenlanmca ?, Beck., var. declivis. 2nd Sup., Tab. Ill, fig. 12 a — b ; Crag 



Moll., vol. i, p. 146, Tab. XII, fig. 5 ; 

 1st Sup., p. 75. 



Axis f ths of an inch nearly. 



Locality. Red Crag, Butley. 



The shell now figured differs so materially from all the Crag Naticce that I have been 

 at a loss to what it should be referred. Its elevated spire almost brings it into what has 

 been generically called Amauropsis, but as I believe it to be a true Natica I have pre- 

 ferred to give it here simply as a very abnormal form of some known species of that 

 genus ; and as N. Groenlandica seems to answer to it in respect of the more reliable 

 characteristics upon which the species of Natica have been separated, and is withal a variable 

 species, it is to this that I provisionally assign it as a variety {declivis). I am reluctant to 

 assign new specific names on the evidence of a solitary specimen where the distinction of 

 it from any other known form is not clear, but if further specimens of this shell should 

 be found, then I think it might be regarded as a new species under the name declivis. 



Natica triseriata ? Say. 2nd Sup., Tab. Ill, fig. 14, a — b. 



Natica trisekiata, Say. Journ. Acad. Nat. Sci., v. 211 {fide Gould). 

 — — Gould. Invert. Massachusetts, p. 233, fig. 165. 



Axis 1 inch. 



Locality. Red Crag, Butley. 



