214 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 6 



Bolivina subexcavata Cushman and Wickenden 

 Plate 27, Figs. 3, 4 



Bolivina subexcavata Cushman and Wickenden, Proc. U.S. Nat. 

 Mus., vol. 75, art. 9, 1929, p. 9, pi. 4, figs. Aa, b. — Cushman, Special 

 Publ. 9, Cushman Lab. Foram. Res., 1937, p. 138, pi. 18, fig. 33. 



Test small, broadest near the apertural end, from which it rapidly 

 tapers to the initial end, periphery rounded ; chambers few, consisting of 

 6 or 8 pairs, the earlier ones broad and low, the later ones increasing in 

 height toward the apertural end ; sutures distinct, depressed, slightly 

 oblique ; wall very coarsely perforate with 2 regions, one at either side of 

 the central area, which are excavated ; aperture an arched indentation at 

 the base of the last-formed chamber in the median line. Length 0.32 mm. ; 

 breadth 0.18 mm.; thickness 0.12 mm. 



The types are from ofif Juan Fernandez. It is a peculiar small form, 

 marked by the coarse perforations, and the 2 distinct ridges close to the 

 median line. It is similar to B. pseudoplicata Heron-Allen and Earland, 

 from off the British Isles, and also resembles B. plicatella Cushman, but 

 has a much less developed sculpture than either. Similar specimens occur 

 widely distributed in the Tropical Pacific. 



In our material "the species occurs at numerous stations and seems to 

 grade into the form here referred to B. pseudoplicata. 



Stations: 61, 76, 136, 213, 232, 233, 323, 413, 466, 469, 472, 500, 

 502, 503, 539, 1009, 1041, 1062, 2066. 



Distribution. — In shallow waters from Monterey, California, in 25 

 fms., southward off the Channel Islands in 20 to 52 fms. ; off Mexico and 

 in the Gulf of California in 9 to 22 fms.; off Galapagos in 10 to 35 fms.; 

 and off Ecuador in 10 to 19 fms. 



Bolivina tongi Cushman, var. filacostata Cushman and McCulloch, 



new variety 

 Plate 27, Figs. 7-11 



Variety differing from the typical in the more highly ornamented test 

 which in the later portion particularly consists of many fine, threadlike 

 costae. 



Holotype of variety (AHF no. 45) from Station 461. 



When compared with the types of B. tongi Cushman from the Mio- 

 cene, the similarity is very striking; but the living form, which in some 



