224 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 6 



Loxostoma mayori Cushman and Parker (not Cushman), Proc. U.S. 

 Nat. Mus., vol. 80, art. 3, 1931, p. 16, pi. 3, fig. 24. 



Variety differing from the typical form of the species mainly in the 

 addition of longitudinal costae, usually few in number, and mostly near 

 the base of the test. Length up to 2.00 mm. ; breadth 0.40 mm. ; thickness 

 0.20 mm. 



This variety sometimes merges with the typical form, but the two 

 seem rarely to occur together. 



Stations: 424, 500, 501, 503, 504, 2084. 



Distribution. — An analysis of the station records places this species ofif 

 Socorro Island, Mexico, in 17 to 46 fms. and olif La Libertad, Ecuador, 

 in 4 to 25 fms. 



Loxostoma mayori (Cushman) 

 Plate 28, Figs. 11, 12 



Bolivina mayori Cushman, Publ. 311, Carnegie Instit. Washington, 

 1922, p. 27, pi. 3, figs. 5, 6; Bull. 104, U.S. Nat. Mus., pt. 3, 1922, p. 40; 

 Publ. 342, Carnegie Instit. Washington, 1924, p. 19, pi. 6, figs. 3, 4; 

 Publ. 344, 1926, p. 76. 



hoxostomum mayori Bermudez, Mem. Soc. Cubana Hist. Nat., vol. 

 9, 1935, p. 197. — Cushman, Special Publ. 9, Cushman Lab. Foram. Res., 

 1937, p. 195, pi. 22, figs. 16-21 ; Smithsonian Misc. Coll., vol. 99, no. 9, 

 1941, p. 11. 



Test elongate, slender, often arcuate or somewhat twisted, somewhat 

 compressed, periphery rounded, the early portion somewhat tapering, 

 later with the sides nearly parallel throughout their length ; chambers nu- 

 merous, distinct, becoming gradually higher as added until, in the later 

 development, the height becomes greater than the breadth, and the last- 

 formed chambers uniserial but usually with oblique sutures, and some- 

 what more rounded in form than the early portion ; sutures distinct, lim- 

 bate, slightly depressed, more so in the later portion, in the early portion 

 oblique and nearly straight, later becoming sigmoid as the chambers tend 

 to become uniserial ; wall coarsely perforate, the perforations often in lon- 

 gitudinal lines, and surface with a few, short, weakly developed costae; 

 aperture in the adult terminal, narrowly elliptical, often with a slight 

 rounded lip. Length up to 2.00 mm.; breadth 0.30 mm.; thickness 0.20 

 mm. 



This is a widely distributed species in rather shallow tropical and 

 subtropical regions. The specimens recorded here are somewhat variable 



