362 TRANSACTIONS OF THE WAGNER FREE 



growth are mucli elevated. Alt. 11 ; max. diam. 18 mm. Tlie stellate margin, 

 nearly smooth surface and conical form will distinguish it easily from any 

 other American Tertiary species. 



Onustiis annosHS of Conrad (Am. Journ. Conch, v. p. 42, pi. i. fig. 4), 

 from the Shark River Eocene of New Jersey, is a Solarium of the group of 

 5. elaboratiivi, and does not belong to this family at all. It is probably the 

 same as one of the southern species, but the specimens found, so far, are too 

 poor to determine this with certainty. 



Family NATICID^. 



Genus NATIOA (Adanson) Scopoli. 



Natica (Adans.) Scopoli, Introd. Hist. Nat., p. 392, 1777 ; Bruguiere, Enc. Meth. i. p. xvi., 



1789; Lamarck, Prodrome, p. 77, 1799. 

 Cochlis Bolten, 1798, + Nacca Risso, 1826. 



In introducing Adanson's name into binomial nomenclature Scopoli cited 

 four examples, of which two are genuine Naticas as of late restricted, N. rufa 

 Born and N. vitellus Linne, one was a Neverita (albumen L.), and the fourth 

 an Ampullaria-\\ke shell, Nerita Itisitanica Linne, variously identified by dif- 

 ferent authors. 



Lamarck's type was N. canrena, so it may be considered positively set- 

 tled that the typical Natica has an umbilicus furnished with internal ribs and 

 a sulcate shelly operculum. The extent of the genus is so great that it seems 

 advisable to divide it ; though, as pointed out clearly by Zittel, the forms so 

 distinct in the existing seas are more or less closely united by their fossil rep- 

 resentatives. For present purposes we may refer to Natica Scopoli i^noii Risso 

 + Nacca Risso) all the species having a calcareous operculum, while for those 

 having a horny operculum (the oldest name, Uber Humphrey, not having 

 been defined) we must probably adopt Polynices Montfort, 18 10. Ampidlina, 

 which seems to have been suggested in the vernacular by Faujas St. Fond as 

 early as 1 803, and was hesitatingly dealt with by Lamarck, Defrance and 

 others without being formally defined or adopted, was finally introduced into 

 systematic nomenclature by Bowdich in 1822 (Elem. Conch, i. p. 31). Each 

 of these groups is susceptible of further division into sub-genera, on charac- 

 ters drawn from the features of the shell. Under Natica proper, among others, 

 we have Cochlis (Bolt.) Morch for the species with a single marginal rib to the 

 operculum, Natica s. s. for those with a multisulcate operculum, Stigviaulax 

 Morch for those with a sulcate or reticulate shell, and Cryptonatica Dall for 

 those forms with a smooth calcareous operculum and an umbilicus entirely 

 and smoothly filled with callus, such as N. clausa B. and S., N. russa Gould, 

 N. pusilla Say, etc.; all the previously enumerated groups having the umbili- 

 cus open and more or less complicated by spiral grooves or ribs which ter- 

 minate bluntly at the margin of the aperture. 



In discussing this genus in its widest sense, it should be borne in mind 

 that there is a certain difference of form between the sexes. The males, as 



