44 



BULLETIN 161, UNITED STATES NATIONAL MUSEUM 



NONION PACIFICUM (Cushman) 



Plate 10, Figures 9a, b 



Nonionina umhilicatula (Montagu) var. pacifica Cushman, Carnegie Inst. 



Washington Publ. 342, p. 48, pi. 16, fig. 3, 1924. 

 Nonion umbilicatulum (Montagu) var. pacificum Cushman, Bull. Scripps Inst. 



Oceanogr., Tech. Ser., vol. 1, no. 10, p. 49, pi. 2, fig. 5, 1927. 



Test much compressed, entirely involute, slightly umbilicate, 

 periphery rounded; chambers distinct, usually about eight in the last- 

 formed coil, not inflated; sutures distinct, not limbate, very slightly 

 curved; wall smooth, finely and evenly perforate; aperture an elongate, 

 narrow' slit, at the base of the apertural face. Length, 0.6 mm; 

 breadth, 0.5 mm; thickness, 0.3 mm. 



This was originally described from Samoa as a variety of Montagu's 

 species. As Montagu's species is more or less uncertain in its char- 

 acters, and as our form seems to be widely distributed in the Pacific, 

 it seems best to refer to it as a definite species as was indicated at 

 the time that it was originally described from Samoa. It is widely 

 distributed in the Pacific, and our specimens are from Albatross 

 stations in deeper water, data for which are given in Table 24. There 

 is some variation in the degree of compression of the test, in the depth 

 of the umbilici, and in the fineness of the perforations of the surface. 



Table 24. — Nonion pacificum — material examined 



U.S.N.M 

 No. 



22245 

 22246 

 22247 



22248 



22249 

 22250 

 22251 

 22252 

 22253 



22254 



22255 

 22256 



22257 

 22258 

 22259 

 22260 

 22261 



Num- 

 ber of 

 speci- 

 mens 



Alba- 

 tross 

 station 



H3787 

 E3791 

 H3796 



HSSIO 



H3826 

 H3832 

 H3837 

 H3838 

 H3841 



H3858 



H3870 

 H3875 



H3888 

 H3890 

 H3896 

 H3935 

 H3936 



Locality 



Lat. 6° 41' N., long. 137° W 



Lat. 7° 58' S., long. 139° 9' W._. 

 Haunanu Point, Ua Huka Island 



Marquesas, 43° S., 1554 miles E. 

 Entrance to Avatoru Pass, Ra- 



hiroa AtoU, 3.5 miles S. 

 Lat. 14° 56' S., long. 148° 44' W._. 

 Lat. 15° 33' S., long. 148° 45' W... 

 Lat. 16° 32' S., long. 148° 40' W.. 

 Lat. 16° 57' S., long. 148° 58' W. 

 Point Venus, Tahiti Island, 32° 



S., 4.2 m.iles W. 

 Ngaruae Pass, Fakarava Atoll, 



28° S., 1 mile E. 

 Village, point of Anaa Atoll, 50° 



S., 5 miles W. 

 Southwest point of Tahanae, 



about H mile offshore, 3 hiiles 



NE. 

 Lat. 16° 14' S., long. 142° 50' W. 

 Lat. 16° 25' S., long. 143° 33' W. 



Tekokoto Atoll, 1 mile E 



Hereheretue Atoll, 1 mile W 



Hereheretue AtoU, 0.3 mile E 



Depth 



Fath- 

 oms 

 2,776 

 2,287 

 1,040 



661 



711 

 2,267 

 2,363 

 2,224 



775 



599 



1,110 



269 



1,510 



1,108 



617 



594 



189 



Bot- 

 tom 

 tem- 

 pera- 

 ture 



°F. 



35.5 

 36.1 

 38.4 

 39.5 

 62.1 



Character of bottom 



It. gy. glob, oz 



gy. yl. oz. crs. glob 

 gn. oz. lav 



wh. CO. s. glob. oz. 



min. frag. 



wh. pter. oz 



It. gy. oz. glob 



vol. m. glob 



do.-- 



crs. vol. s. mang. 



nod. 

 crs. CO. s 



fne. CO. s. pter. oz. 



glob, 

 crs. CO. s 



glob. oz. mang-- 

 do 



crs. CO. s 



CO. s. mang. part- 



Occur- 

 rence 



Rare. 

 Do. 

 Do. 



Do. 



Do. 

 Do. 

 Do. 

 Do. 

 Do. 



Do. 



Do. 



Do. 



Do. 

 Do. 

 Do. 

 Do. 

 Do. 



