1 68 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



Affinities: Cossmann compares this species with C. podolicum (Dub.) 

 from the upper Miocene (Sarmatian) of southeast Europe, and C. pseudo- 

 tnrricula Dollf. from the middle Miocene of France. There is no doubt 

 that the first one (C. podolicum, see Hoernes, 1856, p. 447, pi. 45, f. 2) 

 represents a similar type, although the details of sculpture are different. 



100. CALLIOSTOMA GARRETTI Ortmann. 



PI. XXXI, Fig. 6"'". 

 1900 C. g. Ortmann, in: Amer. Journ. Sci., v. 10, p. 373. 



Shell conical, as high as broad, not umbilicated. Eight whorls, which 

 are very slightly convex; suture shallow. Last whorl very bluntly 

 angular at the periphery, without a distinct peripheral keel. Surface of 

 whorls, above the periphery, covered with numerous fine revolving threads : 

 there are, on the third whorl, about 7 of them, increasing to about 17 on 

 the last whorl. The number of threads increases by intercalation, the 

 new ones being at first smooth ; with increasing size they equal the older 

 threads, and become, like the latter, finely but distinctly granulated. These 

 granulations, however, are developed only in the upper three quarters of 

 the whorls : the lower 4 or 5 threads remain smooth. Intervals between 

 the threads about as broad as these, and crossed by very fine lines of 

 growth, giving a pitted appearance to them. The revolving threads con- 

 tinue over the periphery to the base of the shell, which is slightly convex ; 

 their number is about 24 on the base, and they are smooth, without granu- 

 lations, resembling in all other respects those of the upper part of the 

 whorls. 



Height, 17 mm; diameter, 17 mm. 



Remarks: The specific name is given in honor of Mr. J. W. Garrett. 



Record of specimens: Mouth of Santa Cruz River, 6 sp. 



Affinities: Trochus macspormni Philippi (1887, p. 102, pi. 12, f. 6), 

 from the island of Santa Maria, Chili (Navidad beds?) seems to represent 

 this species in Chili, but in T. macsporrani the granulations are wanting, 

 and the periphery is more sharply angulated. 



C. garretti exhibits distinctly Miocene relations, with a group of species 



found in Miocene beds of the southern United States, described by Ball 



(1892, p. 390 ff., pi. 18 and 22). The most closely allied of them seem 



to be: C. philanthropies (Conr.) (see: 1. c., p. 390, pi. 18, f. ga) from the 



