LOWER HELDERBERG ROCKS. 395 



Ilolopea aiitiqua, var. penetasta. 



Plate LIV. Fig. 4 & 5. 



Among the specimens figured by Mr. Conrad under the name Littorina pervehista, 

 I find those referred to on Plate liv as above. I have given the figures as they are 

 drawn, one representing a cast and the other the shell. In the latter the columella 

 is represented as slightly reflexed, but the umbilical groove is scarcely perceptible. 



This one may be a distinct species; but as the H. antiqua presents considerable 

 variety of form in the casts which have come under my observation, I prefer, for 

 the present, to consider it a variety of that species. 



The specimens figured are from the Tentaculite limestone, but the particular 

 locality is not mentioned by Mr. Conrad. 



Ilolopea danai ( n. s.). 



Plate LIV. Fio. 14. 



Shell ovoid-conical, the spire tapering abruptly : volutions about five, 

 convex, the last one extremely ventricose and equalling in height the 

 remaining ones : euture, in the cast, deeply impressed, and the upper 

 margins of the volutions truncate. Surface unknown. 

 The cast retains something more than three volutions, and there appear to have 



been two more at the apex. 



This species differs from the preceding in the more rapid diminution of the spire 



above the last volution, and in the truncated upper edges of the volutions. It beai-s 



some general resemblance to H. paludinaformis of the Trenton limestone, but the 



spire is longer and more conical. 



Fig. 14. Anterior view of the cast of this species. 

 Geological position and locality. In the pentamerus limestone at Chittenango falls. 



Ilolopea t eloiigata ( n. s.). 



Plate LIV. Fig. 6 & 7. 



Shell elongate, subfusiform : spire very gradually tapering ; volutions 

 about five or six, regularly rounded, the last one moderately ventricose ; 

 columellar lip slightly thickened and reflexed. Surface unknown. 



