194 P0RAMIN1FERA OF THE CRAG. 



Occurrence. — Lagena hexagona has a wide bathymetrical range. The ' Chal- 

 lenger ' specimens were obtained at depths ranging from 40 to 2425 fathoms, 

 but exclusively from stations in temperate and tropical seas. It is worthy of note 

 that no specimen of L. hexagona is recorded in the ' Challenger ' Report from the 

 dredgings in high latitudes, whereas L. squamosa was found commonly in those 

 areas. 



The geological history of L. hexagona, like that of its congeners L. melo and 

 L. squamosa, is not known at present to extend beyond the Tertiary period. It 

 has been found in the Oligocene of Elsass, the Miocene of Italy, Vienna, and of 

 Muddy Creek (Victoria), the Pliocene of Garrucha (South Spain), Piedmont, and 

 St. Erth, and in beds of Pleistocene age in Scotland and Ireland. We have 

 ourselves found it in the Scaldisiau of Antwerp. In the Coralline Crag it occurs 

 at Broom Hill, zone d, Gedgrave, zone f, and Sutton, zones e and f. 



13. Lagena seminuda, Brady, 1884. Plate VI, figs. 8 a, b. 



Lagena seminuda, Brady, 1884. Keport 'Challenger,' pp. 446 and 472, pi. lviii, 



figs. 34 a, b. 



Characters. — Test subglobular or somewhat pyriform ; orifice in a crater-like 

 depression on the truncate oral extremity ; surface ornament consisting of a raised 

 reticulation (hexagonal in PI. VI, fig. 8, and less regular in Brady's figure), 

 confined to the lower half of the shell; the remainder being smooth. 



The striking characteristic of L. seminuda, is its truncate oral end, and this 

 feature is very constant. Of the many specimens found in the Coralline Crag, not 

 one shows any approach to a produced neck. In its surface ornamentation 

 //. seminuda presents the same relation to L. hexagona as L. eosfata, Williamson, 

 does to L. sulcata, W. and J., and L. semistriata, Williamson, to L. striata, 

 d'Orbigny. In L. seminuda, L. costata, and L. semistriata the specific ornamenta- 

 tion is located on the posterior portion of the test, and may partially invest the shell 

 (o a, greater or less degree anteriorly. It appears to be a characteristic of the 

 Lagenss that where only a portion of the test is furnished with a particular type of 

 ornamentation, that portion includes the aboral extremity. 



Occurrence. — L. seminuda was described for the first time by Brady in the 

 'Challenger' Report. On reference to the tables at the end of the Report we 

 find I hat the 'Challenger' specimens were obtained from the temperate zone at 

 depths ranging from 1375 to 2350 fathoms. The bottom temperatures varied 

 from 0' I C to 1*5° C. In the body of the Report, Brady states that it has been 

 found in shallower waters in the North Atlantic. 



