ORTMANN I TERTIARY INVERTEBRATES. 165 



Affinities: In the Navidad beds of Chili we have a closely allied species, 

 T. fricki. I cannot say, however, that any species of the northern hemi- 

 sphere shows a marked affinity to this one, although there are many, which 

 might be compared with it. 



96. CALLIOSTOMA OBSERVATIONS Ortmann. 



PI. XXX, Fig. i3 a -. 

 1900 C. o. Ortmann, in: Amer. Journ. Sci., v. 10, p. 372. 



Shell low, conical, not umbilicated. Whorls flat, last whorl bluntly 

 angular on the periphery. Above this angulation there are 5 distinct 

 revolving ribs ; near the mouth, between the 2d and 3d (counted from the 

 upper part), a sixth rib begins to appear, and, in our largest individual, the 

 peripheral angulation is divided by a fine impressed line into two ribs. 

 On the upper whorls, near the apex, the 2d and 4th ribs disappear, so 

 that only three ribs remain (ist, 3d, and 5th), besides the peripheral 

 angulation, which appears as a 4th rib immediately above the suture. All 

 the ribs, when fully developed, are subequal, flattened, smooth, about as 

 broad as the intervals between them. The base of the shell shows 910 

 revolving ribs of the same character, which are, near the umbilicus, as 

 broad as the intervals, but more crowded toward the periphery. The 

 outermost of them is not separated from the peripheral angulation by a 

 broader interval. 



Height, 10.5 mm; diameter, 12 mm. 



Remarks: The lack of granulations distinguishes this species at once 

 from C. fricki and philippii. Furthermore, in C. fricki, the spire is more 

 depressed, but more acute ; the revolving ribs of the base are more 

 crowded, and a small umbilical excavation is present. 



Record of specimens : Mt. of Observation, upper horizon ; 10 sp. 



97. CALLIOSTOMA PERARATUM Cossmann. 



PI. XXXI, Fig. 3"' ". 



1899 C. p. Cossmann, in : Journ. Conchyliol., p. 9 (of sep. cop.), pi. 10, f. 6. 



Shell conical, about as high as broad, not umbilicated. Whorls flat, 



last whorl bluntly angulated. Upper whorls with 2 strong and i finer 



revolving keels ; the lower keel is formed by the peripheral angulation ; 



