ORTMANN I TERTIARY INVERTEBRATES. 241 



Remarks: There are slight variations in sculpture. The number of 

 longitudinal ribs varies between 12 and 17 in our individuals; v. Ihering 

 gives 1 8 for the last whorl, but his specimen is larger than any of ours. 

 The nodulose appearance of the upper end of the ribs is more or less dis- 

 tinct: sometimes the ribs only end suddenly without forming a node. 

 The spiral cords are unequal, with from i to 4 smaller cords between the 

 stronger ones. The nodulose appearance of these cords is sometimes 

 quite distinct, sometimes hardly indicated. 



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



Distribution: Santa Cruz and La Cueva, Suprapatagonian beds (v. Ih.). 



Affinities: The European Miocene species P. intorta Brocchi (Hoernes, 

 1856, p. 331, pi. 36, f. i, 2, especially fig. i) resembles the Patagonian 

 form so closely that it is difficult to point out the difference ; but it seems 

 that in P. intorta the longitudinal ribs are less distinct, and their upper 

 noduliferous termination is more strongly developed. The Pliocene form 

 of P. intorta (Wood, 1848, p. 53, pi. 6, f. 4) differs more from our species. 



Gen. DRILLIA Gray. 

 1 68. DRILLIA SANTACRUZENSIS Ortmann. 



PI. XXXVII, Fig. 3"> s . 



1900 D. s. Ortmann, in: Amer. Journ. Sci., v. 10, p. 376. 



Shell turrite, subfusiform. Last whorl hardly half as long as the shell. 

 Whorls 8, convex, but depressed and slightly concave in the upper part, 

 near the suture. This depression forms a shallow groove, following the 

 suture, and is sharply separated from the rest of the whorl, which is orna- 

 mented by oblique longitudinal ribs, which end abruptly at the sutural 

 depression. The number of these ribs is from 12 to 15. Besides, there 

 are very fine lines of growth, but no trace of spiral sculpture. Mouth 

 elongate, canal short. Sinus of outer lip semicircular, situated in the 

 sutural depression, close to the suture; at the point of junction of the 

 outer lip with the columella (in the upper angle of the mouth) there is a 

 distinct nodulose, callous swelling. 



Height, 13 mm; diameter, 4.5 mm. 



Remarks : The most characteristic features of this species are : ( i ) The 

 callosity of the upper end of the inner lip. (2) The sharply defined 

 sutural depression. (3) The complete lack of spiral sculpture. 



