72 
PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 
Distribution : Gulf of San Jorge, Patagonian beds (v. Ih.). Specimens 
sent by v. Ihering to the U. S. Museum and examined by the writer were 
labelled : Santa Cruz. 
Affinities : The most closely allied species, R. nigricans , has been found 
living at New Zealand, and fossil in the Oamaru, Pareora and Wanganui 
beds of New Zealand, and thus it ranges from the Oligocene upward to 
Recent times. 
1 6. Rhynchonella squamosa Hutton. 
PI. XII, Fig. 4"T 
1873 Rhynchonella squamosa Hutton, Cat. Tert. Moll. Echin., New Zea- 
land, p. 37. 
1878 R. codata Tenison- Woods, Journ. Proc. Roy. Soc. N. S. Wales, v. 
11, p. 77. 
1880 R. squamosa Tate, in: Trans. Proc. Roy. Soc. S. Australia, v. 3, p. 
166, pi. 9, f. 9. 
1880 R. nigricans van. pixydata Davidson, Challenger Brach., p. 59, pi. 
4, f. 14. 
1887 R. nigricans van. pixydata Davidson, in: Trans. Linn. Soc., ser. 2, 
v. 4, p. 170, pi. 24, f. 10. 
1896 R. squamosa Pritchard, in: Proc. Roy. Soc. Victoria, v. 8, p. 143. 
1900 R. squamosa Ortmann, in: Amer. Journ. Sci., v. 10, p. 378. 
Shell more or less transversely circular ; beak acute and incurved. For- 
amen small. Dorsal (small) valve convex, mesial fold scarcely distin- 
guishable. Ventral valve flatter, with a broad, well-defined mesial sinus. 
Surface of both valves with about 40-50 radiating ribs, 10-15 of them in 
the sinus ; closely intersected by squamose, concentric lines of growth, 
giving an imbricated appearance to the surface. 
Length 24, 25, 25 mm. 
Width 26, 28, 26 mm. 
Remarks: Davidson confirms the identity of R. codata with his R. pixy- 
data, , and — as Tate points out — R. codata is distinguished from R. nigri- 
cans by the same characters that distinguish R. squamosa , being accord- 
ingly the same as the latter. 
Our individuals agree well with the figures of R. squamosa , as well as 
of R. pixydata , especially in the squamose surface markings. The only 
