184 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



Gen. CREPIDULA Lmck. 

 115. CREPIDULA GREGARIA Sowerby. 



PI. XXXII, Fig. io<-. 



1846 C.g. Sowerby, in: Darwin, Geol. Observ. S. Amer., p. 254, pi. 3, 



f. 34- 

 1864 C. incurva Zittel, in: Novara Exp. Geol., p. 44, pi. 15, f. 9. 



1873 Crypta i. Hutton, Catal. Tert. Moll. Echin. New Zealand, p. 14. 

 1887 Crepidula uncinata Philippi, Tert. & Quart. Verst. Chiles, p. 94, pi. 



11, f. 6. 



1887 C. gregaria Philippi, ibid., p. 94, pi. 12, f. i (after Sowerby). 

 1887 Haliotis imperforata Philippi, ibid., p. 102, pi. 12, f. 2. 

 1897 Crepidula gregaria v. Ihering, in: Rev. Mus. Paul., v. 2, p. 278. 



Shell oblong, thick, smooth, except for growth-lines, very convex. 

 Apex incurved, marginal, sometimes a little produced ; apical margin of 

 mouth thickened. Diaphragm concave or plane, reaching about to the 

 middle of the shell or slightly beyond, its margin concave. 



Measurements of largest individual from Punta Arenas : Length, 92 

 mm, width, 44 mm, height, 34 mm. 



Remarks: This shell is very variable in shape, broader or narrower. 

 The apex, in smaller individuals, is produced and prominent beyond the 

 line of the curvature of the margin of the shell, and simply incurved ; in 

 very old and large individuals it is subspiral, and raised a little upon the 

 upper surface. 



C. incurva of Zittel is no doubt this species : the figure agrees perfectly 

 with our complete specimen of small size from Santa Cruz. 



C. uncinata of Philippi is also a small individual of this species. 



Haliotis imperforata Phil, comes from Skyring Water: there is no 

 doubt that our giant specimens from Punta Arenas represent this form, 

 and they are nothing but very large C. gregaria. 



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

 almost complete) ; Upper Rio Chalia, 31 casts; Arroyo Gio, 3 sp. ; Punta 

 Arenas, horizon V (Patagonian), 6 sp. ; (5 of them very large). 



Distribution: Santa Cruz (Sow.) ; Jegua quemada and La Cueva, Pata- 

 gonian and Suprapatagonian beds (v. Ih.) ; Navidad beds of Chili : Lebu, 

 Matanzas, Guayacan, La Cueva (Phil.). 



