INSTITUTE OF SCIENCE, PHILADELPHIA. 373 



Polynices (Lunatia) perspectivus Rogers. 



Natica perspectiva Rogers, Trans. Am. Phil. Soc, 2d Ser. v. p. 332, 1837 ; ibid. vi. pi. 



xxvi. fig. 3, 1839. 

 Natica caroliniana Conrad, Am. Journ. Sci. xli. p. 346, pi. 2, fig. 18, 1841 ; Am. Journ. 



Conch, iv. p. 65, pi. 6, fig. 3, 1868. 

 Not N. carolinia7ia Tuomey and Holmes, Pleioc. Fos. S. C, pi. 25, fig. 18, nor of Conrad, 



Proc. Acad. Nat. Sci. Phila. 1862, p. 564, 1863. 



Chesapeake Miocene of St. Mary's River and Plum Point, Md., of Wil- 

 liamsburg, Va., and of Duplin County, N. Carolina. 



This is N. heros Conrad, ex parte, 71011 Say, and N. hemicrypta Conrad, ex 

 parte, not of Gabb. The species is much the same shape as L. triseriata Say, 

 of the recent fauna, but larger, heavier, and with a different umbilicus. It may 

 be recognized by its smoothly arched spire, in which the rotundity of the 

 whorls is not marked and the suture is smoothly appressed, as in a male 

 Neverita duplicata of the elevated variety ; by its umbilicus, which is wide 

 below and obscurely spirally striate, with near the top of the umbilical wall a 

 sharp narrow spiral rib, which terminates between two obscure notches on 

 the columellar callus. It is a narrower, heavier and smaller shell than the 

 average adult L. heros, though decorticated specimens, such as abound in the 

 marls, are sometimes difficult to recognize. Conrad's figures (Am. Journ. 

 Conch, iv. pi. 6, fig. 3, etc.) are bad, representing immature and depressed 

 specimens, and exaggerating the size of the umbilicus and the .spiral rib. 



Polynices (Lunatia) heros Say. 



Natica heros Say, Journ. Acad. Nat. Sci., ist Ser. ii. p. 248, 1822 ; Gould, Inv. Mass., p. 231, 



fig. 163, 1841. 

 Lunatia heros Dall, Bull. 37 U. S. Nat. Mus., p. 154, pi. 51, figs, i, 11, 18S9. 



Chesapeake Miocene of Jones's Wharf, St. Mary's River, and Little Cove 

 Pc, Maryland, and various points in Virginia ; Post-Pliocene of Massachu- 

 setts, at Sankoty Head, and living on the eastern coast of the United States 

 from Labrador to Hog Island, Virginia, in i to 238 fathoms. 



This species does not appear to have extended its range south of North 

 Carolina, the citations for more southern localities referring usually to L. iii- 

 ierna ox perspectiva. The form, which may, perhaps, be a distinct species, L 

 triseriata of Say, I have not been able to recognize among the fossils, though 

 Verrill reports it from the Post- Pliocene of Sankoty Head. 



This species is somewhat variable, and the difference between the sexes 

 is very marked. In a pair from Nova Scotia having each a height of 50 mm. 

 the male measured 40 mm. in maximum diameter and the female 45 mm. 

 The difference in form is even greater than these measurements would imply. 

 The deep-water specimens are thin, but grow to a very large size. This species 

 is especially subject to decortication in the fossil state, and when so mutilated 

 is difficult to recognize. Perfect adult specimens can usually be identified by 

 their globose form, rounded but not turrited whorls, small ribless umbilicus 



