196 PATAGONIAN EXPEDITIONS I PAL/EONTOLOGY. 



growth, and appearing distinctly crenulated, but not granulated. Be- 

 tween the principal ribs are i to 3 fine striae, becoming more numerous 

 \vith age. 



Measurements of largest fragment : Height, 58mm; diameter, 14 mm. 



Remarks: Of the principal ribs, the uppermost is always the strongest, 

 forming a distinct angulation. In most of the cases, the lowermost rib is 

 the second in thickness, and the middle one is the finest. But in some 

 cases the lowermost is finer than the middle one, and such individuals 

 represent v. Ihering's T. tricincta. In young individuals the suture is 

 very shallow. 



Large individuals of this species are easily recognizable by the more 

 elongated and more slender form, and by the thick revolving ribs. But 

 young individuals and fragments, especially if a little worn, are almost 

 indistinguishable from T. ambulacrum, since the slender form is not so 

 evident. It is possible that some of the individuals recorded under T. 

 ambulacrum belong really to this species. 



Record of specimens: Mouth of Santa Cruz River, 7 sp.; Paso del Rio 

 Santa Cruz, i sp.; Las Salinas, 3 sp. (one of them a cast); Mt. of Obser- 

 vation, lower horizon, 2 sp. (one of them a typical T. tricincta}. 



Distribution: Chiloe (Phil.); Santa Cruz (Phil., v. Ih.); Jegua quemada 

 (v. Ih.): Patagonian and Suprapatagonian beds (v. Ih.). 



Affinities: T. perattenuata Heilprin (see: Dall, 1892, p. 316, pi. 16, f. 

 5, 9), from the Pliocene of Florida has a general resemblance, but seems 

 to be more slender. There are (according to Dall) Miocene species, which 

 resemble T. perattenuata, especially T. terebriformis Dall (p. 31 1), but since 

 there is no figure published, I cannot say what are the relations to T. 

 breantiana. At any rate, we must take T. breantiana as a species of Neo- 

 gene relations. 



126. TURRITELLA PATAGONICA Sowerby. 

 PI. XXXI, Fig. is"' 6 . 



(?) 1846 T. pat. Sowerby, in: Darwin, Geol. Observ. South America, p. 



256, pi. 3, f. 48. 

 1887 T. darwini Philippi, Tert. & Quart. Verst. Chiles, p. 75, pi. 9, 



f. 7 . 



1887 T. patago nica Philippi, ibid., p. 76 (after Sowerby). 

 1889 T. patag. Rochebrune & Mabille, in: Miss. Cap Horn, v. 6, p. 43. 



