432 DISCOVERY REPORTS 



Reuss's original figure shows an almost equally biconvex test with seven chambers in 

 the final convolution. This typical form occurs at nearly every station, but often in 

 company with well marked variations. At WS 73, 97, 98, 109, 210, 217, either with or 

 without the type, a forrrt. in which the superior face is only slightly curved, almost flat in 

 some specimens, is found. The inferior or oral face has the normal convexity, which 

 appears accentuated by contrast with the other face. At WS 79, 86, 219, the variation 

 takes the form of a highly convex superior, and nearly flat inferior, or oral face. The 

 number of chambers also occasionally varies. At WS 210, the specimens are very large, 

 both typical and flat-topped varieties occur, and many have as many as nine chambers 

 in a convolution. At WS 215 and 248, the same variation occurs, 8-9 chambers being 

 found. This increase in the number of chambers is not in our opinion sufficient to 

 modify the allocation of the specimens to P. karsteni, although it seems to indicate a 

 form intermediate between P. karsteni and P. peruviana, in which latter species eleven 

 chambers go normally to the convolution. Occasional specimens occur with limbate 

 sutures on the superior face, a feature otherwise characteristic of P. peruviana. 



392. Pulvinulina peruviana (d'Orbigny) (Plate XV, figs. 37-39). 



Rotalina peruviana, d'Orbigny, 1839, FAM, p. 35, pi. ii, figs. 3-5. 

 Eponides peruviana, Cushman and Kellett, 1929, WCSA, p. 10, pi. iv, fig. 5. 



One station: WS 73. 



At this station which is in-shore to the north of the Falkland Islands, two specimens 

 were found, which appear to be attributable to d'Orbigny 's species, which was de- 

 scribed originally from the coasts of Peru and Bolivia, and has recently been recorded, 

 after the lapse of many years, from the west coast of South America, in its original 

 locality (ut supra). 



The difference between P. peruviana and P. karsteni lies in the greater convexity and 

 fewer chambers of the latter species. In P. peruviana, there are eleven chambers per 

 convolution, and the sutural lines are also slightly limbate on the superior face. It 

 seems very possible that P. peruviana represents a Pacific, and P. karsteni an Atlantic 

 form, and that the two species are very closely related. 



Paris Types: there are two tubes both labelled "Amerique meridionale". The first 

 contains two specimens, one of which is broken and unrecognizable, the other is a 

 broken and dead shell, of which it can only be said that it may at one time have been 

 recognizable as d'Orbigny 's species. Now, the dorsal face is too decomposed to count 

 the numbers of chambers on which identification would primarily rest ; but it is certain 

 that the specimen never had the limbate sutures of which d'Orbigny makes a point. The 

 second tube contains five specimens, four of which are in good condition. They do not 

 conform to d'Orbigny's description in so far as the sutures are concerned, these being 

 nearly flush or even depressed, but they do generally agree with the form of the species, 

 although none of them has more than ten chambers against the eleven shown in d'Or- 

 bigny's figure. There is no particular constancy in the specimens, and they show a 

 considerable range in convexity. 



