74 PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 



globosa is made by Davidson a synonym of M. venosa (Sol.). (Recent, 

 Falkland Islands and Tierra del Fuego.) Our specimens differ from M. 

 I'ciiosa in the small foramen, which is one of the characters in which M. 

 lenticnlaris is said to differ from M. venosa. The other characters given 

 by Davidson are : beak more incurved, dorsal valve uniformly convex, 

 and size smaller. They are, however, hardly of any value. And further, 

 he mentions a difference in the deltidium, but the latter is described in 

 M. venosa in almost the identical terms. Therefore, judging from the 

 foramen, which is the only reliable character, the Patagonian fossil belongs 

 to M. lenticnlaris, and it agrees surprisingly well with the account of that 

 species given by Suess. 



Record of specimens : High bluffs, S. W. of Lake Pueyrredon, 9 sp.; 

 Lake Pueyrredon, base ; 34 sp. 



Distribution: Recent, New Zealand (Dav.); fossil: Gulf of San Jorge, 

 Patagonian formation (v. Ih.); Oligocene (Oamaru), Miocene (Pareora), 

 and Pleistocene of New Zealand (Suess, Hutt); Oligocene and Miocene 

 of Chatham Islands (Hutt.). 



Gen. TEREBRATELLA d'Orb. 

 1 8. TEREBRATELLA DORSATA (Gmelin). 



PI. XIII, Fig. 7<-. 



1864 Terebratella dorsata Suess, in: Novara Exp. Geol., v. i, p. 57, pi. 



14, f- 6. 



1873 T. d. Hutton, Cat. Tert. Moll. Ech., New Zealand, p. 36. 

 1880 T. d. Davidson, Challenger Brach., p. 44, pi. 4, f. 4. 

 1887 T. d. Davidson, in: Trans. Linn. Soc., ser. 2, v. 4, p. 75, pi. 14, f. 



9-19. 



1900 T. d. Ortmann, in: Amer. Journ. Sci., v. 10, p. 378. 



Shell very variable jn shape, but mostly transversely-oval, wider than 

 long. Valves moderately convex, ribbed or (rarely) smooth. Dorsal 

 valve with a median sinus, ventral valve with a corresponding fold. Beak 

 produced, slightly incurved and truncated by a rather large, circular for- 

 amen. Beak ridges sharply defined. 



Length, 44, 43, 38, 31, 31, 28 mm. 



Width, 36, 45, 40, 26, 29, 22 mm. 



