No. 89.] 109 



LOXONEMA TURRITIFORMIS ( n. s.). 



Shell elongate, slender : volutions six or more, very gradually enlarging to the 

 aperture, rounded upon the back. Aperture oval or ovate. 

 Geological formation and locality. In the same association as the preceding. 



EUOMPHALUS PLANODISCUS ( n.s.)- 



Shell planorbicular : spire depressed, composed of about three volutions vrhich 

 are barely contiguous, the whole in the same plane on the upper side. Volutions 

 slender and very gradually enlarging from the apex, regularly rounded; the last 

 one near the aperture a little flattened above, and the margin of the aperture 

 slightly expanded. 



This species has a more depressed spire than any other known 

 to me in the rocks of New-York. 



Geological formation and locality. In the Goniatite limestone 

 at Manlius, New-York. 



EUOMPHALTTS PLANODISCUS. 



EUOMPHALUS LENS (n.s.). 



Shell small, planorbiform or lenticular : spire composed of about four volutions 

 (three to four or more), the inner ones revolving almost in the same plane, while 

 the last one is slightly depressed. Volutions gradually expanding, the last one 

 angular on the periphery; the upper side flattened and declining, and the lower 

 side somewhat rounded : umbilicus broad and moderately deep, the width 

 about equal to the width of the last volution. 

 The specimens are casts, or with silicified shells, and the surface markings are 



obliterated or obscure. There are evidences of oblique striae from the umbilicus to 



the angular periphery, and a revolving undulation on the lower surface. 



The form of the shell is similar to Pleurotomaria (^Raphistoma') lenticularis; 



but is a little more depressed on the summit, while the inner volutions are more 



rounded. 



Geological formation and locality. In strata associated with Goniatites oweni, 



G. rotatorius, etc. : Rockford, Indiana. 



EUOMPHALUS SPIRORBIS ( n.s.). 



Shell extremely depressed, discoid : spire composed of three or four volutions 

 which, on the upper side, are revolved in the same plane. Volutions slender, very 

 gradually enlarging and not expanding at the aperture; aperture rounded : um- 

 bilicus wide and shallow, and sometimes with the outer edge subangular. Sur- 

 face marked by strong elevated striae parallel to the lines of growth : striae 

 sometimes crenulate. 

 Geological formation and locality. In the same strata with the preceding species. 



