OF CONCHOLOGY. 27 



carbonate of lime. No other specimens from this rock "were 

 sent. It is labelled "Immediate vicinity of Payta." 



AMPULLINA. 

 A. Ortoni, Gabb. 



Shell of moderate size, sub-pyriform ; spire moderately ele- 

 vated ; whorls seven, flattened on top,' rounded on the angle ; 

 suture channelled by a very narrow groove ; body Avhorl broadly 

 convex above the middle, tapering in advance ; marked only by 

 lines of growth. Aperture broad, rounded in front ; outer lip 

 simple ; inner lip encrusted by a thin plate ending in front at 

 the umbilicus. Umbilicus imperforate or characterized by a 

 very small opening ; running into it, and bordering the inner 

 lip in advance is a flattened margin, ending abruptly on the 

 outer side and merging in front into the margin of the aperture. 



Length, 2- in. ; width, 1*5 in. ; length of aperture, 1-6 in. 



Specimens of this species were sent me by Dr. Rairaondi, in 

 very imperfect condition ; but I have been so fortunate as to 

 have had the opportunity of studying a few fossils brought by 

 Prof. Jas. Orton from the same locality, and among them is an 

 excellent specimen of this shell, from which I obtain the specific 

 characters. As compared with A. mutahilis of the French 

 Eocene, it agrees in general form, in the sub-pyriform shape, 

 the compressed tops of the whorls and in the channeled suture. 

 It differs, however, in the inner lip, which, in our species, is more 

 like a specimen before me labelled A. patula, of the English 

 Eocene. In A. Ortoni, however, the incrustation above and 

 behind the umbilicus is much heavier and more defined on its 

 edges than in A. patula. 



CERITHIUM, Brug. 



C. LiEViuscuLUM, Gabb. 



Shell very long, slender, whorls numerous, increasing very 

 gradually in size, sub-flattened on the sides, curving in above 

 and below to the suture which is distinctly impressed. Surface 

 marked only by lines of growth, which are obsolete, except on 

 the last whorl where some are distinctly marked. Aperture sub- 

 quadrate, outer lip sinuous, projecting below ; inner lip obsolete- 

 ly incrusted ; canal short, twisted, notch faint. 



Length, (less the tip) 4'2 in. ; total length about 5*2 in. ; 

 length of aperture, 1'3 in.; width of body whorl, 1-4 in. 



From Prof. Orton, associated with the preceding species. 

 Two shells are in Dr. Raimondi's collection, one from between 



