ORTMANN I TERTIARY INVERTEBRATES. 191 



Affinities: This species approaches more nearly the typical form of N. 

 heros Say (see Ball, 1889, pi. 51, f. n) from Miocene to Recent, but the 

 latter has the suture more depressed. 



122. NATICA CONSIMILIS v. Ihering. 



PI. XXXIII, Fig. 6. 



1897 N. c. v. Ihering, in : Rev. Mus. Paul., v. 2, p. 283, textfig. 12. 

 1899 N. c. v. Ihering, in: N. Jahrb. Miner., etc., v. 2, p. 28. 



Shell subglobular, rather thick, smooth. Spire obtusely conical, about 

 y of the height of the shell ; whorls convex, indistinctly angulated near 

 the distinct and deep suture. Umbilicus small, open, without callus. 

 Columellar lip thin, the free part at the umbilicus slightly reflected and 

 thickened. Mouth large. 



Height, 28 mm ; diameter, 26 mm. 



Remarks: The distinct and sharply depressed suture distinguishes this 

 species from all other Patagonian species of the genus. In partly exfo- 

 liated individuals the suture is very deep. 



It seems doubtful whether N. omoia Rochebrune & Mabille (1885, p. 

 138, and 1889, p. 31), belongs to this species. According to the descrip- 

 tion, the union seems hardly warranted ; but since no figure of N. omoia 

 is given, this question is to remain open. 



There seems to be a slip of the pen in v. Ihering's description of this 

 species in 1899. After describing N. consimilis, he says: It seems prob- 

 able that also N. consimilis belongs here as a synonym. N. subtenuis 

 cannot be the species intended, since it is quite different, and thus this 

 sentence remains unintelligible. 



Record of specimens: Mouth of Santa Cruz River, 16 sp. 



Distribution: Santa Cruz and La Cueva, Patagonian and Suprapata- 

 gonian beds (v. Ih.). 



Affinities: There is quite a number of species in Eocene and Miocene 

 deposits of the northern hemisphere, which resemble this one in external 

 form, but I cannot point any particular one, that agrees with this one 

 more closely than others. 



Note: The Australian species of Natica (Tate, 1893, p. 318, ff.) require 

 closer inspection : there are many forms similar to the Patagonian. 



