ORTMANN I TERTIARY INVERTEBRATES. 233 



except for its larger size, that I do not entertain any doubt as to their 

 specific identity. In a letter, v. Ihering maintains the difference of both, 

 saying that the mouth is much wider in V. pilsbryi. But according to our 

 material, the width of the mouth increases with age, and since our indi- 

 viduals are smaller than v. Ihering's, and agree better with V. domeykoana 

 in the size of the mouth, I believe this supposed character of y. pilsbryi 

 is only a character of age. 



The development of the nodes is variable, especially on the last whorl. 

 In one of our specimens these nodes are much less distinct (see fig. i*). 

 In all other respects our four specimens much resemble one another, and 

 may be recognized at once by the characteristic shape of the shell, which is, 

 in some degree, intermediate between V. dorbignyana and y. ameghinoi. 



Record of specimens : Mouth of Santa Cruz River, 4 sp. 



Distribution: Santa Cruz, Patagonian beds (v. Ih.); Chiloe, Navidad, 

 and Quinquina, Chili (Phil.). As to the occurrence of this species in the 

 Cretaceous beds of the island of Quinquina, compare Philippi, 1. c., and 

 Steinmann, 1895, p. 24. 



Affinities: As v. Ihering points out, this species is closely related to the 

 following species, V. ameghinoi, and to the living V. magellanica Lmck. 

 (see Reeve, 1851, pi. 14, f. 33; Tryon, 1882, p. 98, pi. 29, f. 107, 108; 

 Lahille, 1895, p. 25, especially pi. i, f. 11, pi. 8), and it seems to be es- 

 pecially close to the variety figured by Reeve in fig. 33a, which has nodes 

 on the shoulder, and which seems to be included in Lahille's V. tubercu- 

 lata Wood (Lahille, 1895, pi. i, f. 12, 13 and pi. 7, f. 140-145); we may 

 take it for the ancestral form of V. tubercttlata and magellanica, and the 

 latter would represent the same relation to V. domeykoana, as V. ancilla 

 does to V. dorbignyana. 



161. VOLUTA AMEGHINOI v. Ihering. 



PI. XXXVI, Fig. 2. 



1896 y. a. v. Ihering, in: Nachr. deutsch. malakozool. Ges., p. 97. 



1897 ^ a - v - Ihering, in: Rev. Mus. Paul., v. 2, p. 302, textfig. 17. 

 Shell globoso-ovate. Whorls about 3-4 (besides the apical part). Spire 



very short, conical. Mouth very large, over ^ of the length of the shell. 

 Whorls convex, with a distinct shoulder, which is ornamented by a series 

 of strong tubercles. Upper part of whorls oblique, appressed toward the 



