NO. 3 CUSHMAN AND MCCULLOCH : SOME NONIONIDAE 163 



Distribution. — Type locality, Station 136, is off San Clemente Island, 

 California, in 50 fms. Other records extend the range southward, at Bahia 

 Honda, Panama, in 32 fms. and off the coast of Colombia, in 55 to 116 

 fms. 



Genus GUSHMANELLA Palmer and Bermudez, 1936 



Gushmanella primitiva Cushman and McCulloch, new species 

 Plate 18, Figs. 6-8, 10 



Test bilaterally symmetrical, compressed, periphery rounded, height 

 often twice the breadth, early portion with the chambers in a single series, 

 later with supplementaiy ones, smaller and alternating with the larger 

 primary ones, the test tending slightly to uncoil in final stages ; chambers 

 distinct, the primary ones increasing rapidly in size as added, slightly 

 inflated in the adult, supplementary chambers small and irregular in size, 

 developed slightly more on one side than on the other; sutures veiy dis- 

 tinct, slightly limbate, curved, becoming slightly sigmoid in the later 

 portion in some specimens ; wall thin, translucent, smooth, very finely 

 perforate; aperture at the base of the chamber, low, and occasionally a 

 supplementary one slightly above the base of the apertural face, rarely 

 higher up and apparently connecting with an internal tube. 



Length 0.30-0.45 mm; breadth 0.20-0.30 mm; thickness 0.12-0.15 

 mm. 



Holotype (AHF no. 36) from locality 418. 



This species differs from Cushmanella brownii (d'Orbigny) in the 

 more compressed and smaller test, larger number of chambers, and more 

 primitive apertural characters. 



While the aperture in the middle of the apertural face is rarely seen 

 in this species, its other characters show its relationship to the Atlantic 

 species. It is evidently more primitive. There is a distinct tendency toward 

 uncoiling in the later stages, particularly of the megalospheric form. An- 

 other species from the Pacific, Nonionella translucens Cushman, found in 

 the Indo-Pacific region seems possibly an intermediate form between 

 Nonionella and the species described here. Fig. 9 shows a peculiar form 

 possibly related to C. primitiva. 



Stations: 222, 223, 2082, 339, 342, 343, 409, 418, 422, 423, 436, 460, 

 461, 463, 466, 468, 469, 470, 473, 500, 547, 556, 558. 



Distribution. — Type locality. Station 418, is Darwin Bay, Tower 

 Island, Galapagos, in 17 fms. The northward range is Braithwaite Bay, 



