ART. 25 GENERA SIPHOGENERINA AND PAVONINA CUSHMAN 15 



the test, surface hispid; aperture large, terminal, with a broad 

 everted lip, the border of which often has a series of backwardly 

 pointing, long, acicular spines. 



Length up to 1 mm. 



Distribution. — Except for one record by Brady from the South 

 Atlantic, all other records are from the Indo-Pacific, Brady records 

 it from several South Pacific stations in 12 to 2,075 fathoms. Millett 

 notes it as common in his Malay Archipelago material, and Side- 

 bottom from off the east coast of Australia. Heron- Allen and Earland 

 record it from the Kerimba Archipelago off southeastern Africa and 

 from the Antarctic expedition collections. Egger records it from 

 off western South Africa and off western Australia. I have had 

 abundant material from 50 fathoms at Samoa. Its Indo-Pacific 

 distribution, even though wide, does not include the Philippines nor 

 the islands in the Pacific north of the equator. 



It is very distinct from other species of the genus in the develop- 

 ment of spines from the edge of the lip. 



SIPHOGENERINA MEXICANA, new species 



Plate 5, figs. 4a, b 



Description. — Test small, elongate, slender, the early portion 

 triserial, tapering from a subacute initial end, the later portion 

 cylindrical, composed of several chambers — up to eight — in a straight 

 line; chambers distinct, those of the later portion inflated; sutures 

 distinct, depressed, especially toward the apertural end; wall with 

 numerous, rather course punctae, which are almost entirely confined 

 to the basal half of each chamber, wall toward the early portion of the 

 test with short, longitudinal costae, the later portion of the test 

 smooth, thin, translucent; the apertural end truncate with a broad 

 elliptical aperture connecting with the previous aperture by an in- 

 ternal tubular neck. 



Length up to 1 mm. 



Type specimens. — (Cat. No. 353174 U. S. N. M.) from Rio Buena 

 Vista, 0.5 Ions., 25°E. from Tumbadero Hacienda House, Vera Cruz, 

 Mexico, T. Wayland Vaughan collector. Specimens also are in the 

 United States National Museum collections from other localities in the 

 Alazan clays in the same general region. The species also occurs in 

 the Eocene of the Coastal Plain of the United States. 



This species is undoubtedly the ancestor of S. advena Cushman, 

 now living in the Gulf of Mexico, the Caribbean Sea, and adjacent 

 regions of the western Atlantic. The living species has taken on a 

 compressed character of the test; the ornamentation of the basal 

 portion is somewhat different, having assumed a spinose condition, 

 but the general characters of the two are very much alike. Both 

 have the basal portion of the uniserial chambers punctate and the 

 distal portion clear, although the relative amount of each is different 

 in the two species. 



