268 



DESCRIPTION OF A COLLECTION OF FOSSILS, 



A. Hyattt, n. s., PI. 37, fig. 1, la. 



Shell sub-globose, whorls increasing rapidly in size, rounded; umbilicus small, 

 umbilical face of the whorl vertical, margin rounded, sides very slightly con- 

 verging, dorsum regularly rounded; surface smooth, or only marked by indistinct 

 lines of growth, which bend forward on the inner margin of the whorl, slightly 

 backwards on the middle, and then forward towards the dorsum. Septum 



unknown. 



Measurements. Diameter, 4.5 in.; diameter of umbilicus, 0.7 in.; height of 



body whorl, 2.1 in.; width of aperture, 1.75 in. 



Locality. " Near Canibamba, Prov. of Huamachuco. The rock contains coal. 

 Height 8500 metres." 



Remarks. Closely allied to A. SutherlandicB, Murch., but differs in not narrowing 

 so rapidly towards the dorsum, and in the absence of ribs on the young shell. 

 The surface of the only specimen is well preserved, but the thin shell will not 

 separate from the interior to expose the septum. 



A. Raimondianus, n. s., PL 31, f. 2, 2a. 



Shell varying greatly between the young and the adult form ; flattened dis- 

 coidal, broad on the dorsum; sides nearly parallel; whorls increasing very 

 gradually in size, enveloping about a third of their width ; umbilicus broad, open. 

 Young shell strongly ribbed; ribs of the same size as the interspaces, showing a 

 tendency to be slightly tuberculated on the umbilical angle, beginning at the 

 extreme inner edge of the whorl, in contact with the preceding volution, passing 

 vertically out of the umbilicus, they are inclined very slightly forwards on the 

 sides of the whorl, and, on approaching the dorsum, bend with a short curve 

 strongly forward, producing a slightly rounded, acute angle on the median dorsal 

 line. As the shell grows older the ribs disappear, when it acquires a diameter of 

 about four inches. On the largest specimen, 9 inches in diameter, they are 

 represented by faint undulations ending in an obsolete tubercle on the angle of 

 the umbilicus. The dorsal tongue is also broadly rounded instead of being sub- 



angular. 



Measurements. Diameter, 9 inches ; diameter of umbilicus, 3.5 in. ; width of 

 whorl, 3.5 in.; width of aperture, 1.9 in. 



Locality. " Cerro del Salto del Frayle (or friar's leap), near Chorillo, 3 leagues 

 south of Lima. Same rock as that on the Island of San Lorenzo. But a few 

 metres above the sea." Dr. Raimondi considers this lias. 



Remarks. Of the type of ^. cymodoce, d'Orb., from the Corralline and Kimme- 

 ridge, but diff-ers in having smaller ribs, fewer whorls, and in the strong flexure of 

 the ribs, and lines of growth on the dorsum. 



