12 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 75 



raised beadlike protuberances covering the whole chamber wall 

 between the radial sutures; aperture low, elongate, on the proximal 

 third of the ventral border. 



Holotype—iC&t. No. 20787, U.S.N.M.). From off Corral, Chile. 

 It occurred also off Lota, Chile and Pimentel, Peru in considerable 

 numbers. The early stages are shown in plate 4, figure 4 a-c, and 

 the adult characters in figures 6 a-c. The umbilicus is filled but does 

 not have an isolated plug as in Rotalia. 



EPONIDES, species (?) 



Plate 4, figures 3 a-c 



The small form figured is from off Pimentel, Peru. It is figured for 

 record as it is evidently not an adult specimen and there are no 

 others to give detailed characters. 



Genus ROTALIA Lamarck, 1804 



ROTALIA INCA (d'Orbigny) 



Plate 5, figures 1 a-c 



Rosalina inca d'Orbigny, Voy. Am6r. Merid., 1839, vol. 5, No. 5, "Foramini- 

 feres," p. 45, pi. 7, figs. 1-3. 



Test trochoid, nearly circular in outline, biconvex, of about four 

 whorls, the ventral side more convex than the dorsal, periphery 

 rounded; chambers numerous and very distinct, uniformly increasing 

 in size as added, 10 to 13 in the last-formed coil in the adult, somewhat 

 inflated on the ventral side, ending at the umbilical end in distinct 

 angles; sutures very distinct, slightly limbate above, oblique, not 

 depressed nor raised, below nearly radial, deeply excavated, widening 

 and deepening toward the umbilical end, umbilicus with a plug often 

 broken on the exterior into several small bosses; wall on the dorsal 

 side, smooth and polished, ventrally with two distinct areas, the sides 

 of the chamber especially near the inner end \evy clear and with 

 extremely fine pores, the middle portion of each chamber with coarser 

 pores and much less clear wall; aperture on the ventral side part 

 way between the periphery and central plug. 



Diameter, 0.75 mm.; thickness, 0.40 mm. 



This is evidently the species described by d'Orbigny as common 

 from Callao, Peru. He says it is related to his Rosalina •parkinsoniana 

 which is evidently in turn related to Rotalia beccarii (Linnaeus). 

 This is one of the most abundant species at Corral, Chile, but not 

 found at other stations in the collections. It does not have the 

 beaded edges on the ventral side so characteristic of R. beccarii in 

 its typical form and seems to be close to the forms described from 

 the West Indies but not identical. It is one of the species of the R. 

 beccarii group that should be distinguished in various regions. 



