REPORT ON THE FORAMINIFERA. 
383 
to the nature of the aperture, the term is still employed in the original sense. Two 
subordinate groups of triserial forms have since been established, Chrysalidina and 
Tntaxia, the former for those with porous aperture, the latter for such as have a single, 
round, central orifice; leaving to Verneuilina the larger series, in which the aperture more 
or less resembles that of the typical Textularice. 
The minute structure of the test varies in precisely the same manner and to the same 
extent as that of Textulciria proper. The walls are either coarsely arenaceous, as in 
Verneuilina polystropha, finely arenaceous and smooth externally, as in Verneuilina 
pygmcea, or hyaline and conspicuously perforate, as in Verneuilina spinulosa. Under 
the name Rhynchospira abnormis, von Hantken has figured (Mittheil. Jahrb. d. k. ung. 
geol. Anstalt, p. 69, pi. vii. figs. 17-19) an interesting modification of Verneuilina, in 
which the exterior is ornamented by a number of minute tubercles, scattered with 
some regularity over a portion, or in some cases over the whole, of the surface of 
the shell. 
In the typical condition the test is triangular in contour, and the margins are thin or 
subcarinate; but in those species in which the segments are inflated or subglobular, it 
takes the form of a rounded triserial spire, slightly compressed on three sides. 
No limits can be laid down for the geographical or bathymetrical distribution of the 
genus ; the different species affect different conditions of latitude and depth, and 
in one or other of its various modifications it is found over the whole world. Its earliest, 
appearance, geologically speaking, is in rocks of the Cretaceous period, and its occurrence 
is recorded in microzoic formations of almost every subsequent age. 
Verneuilina triquetra, Munster, sp. (PI. XLVII. figs. 18-20). 
Textularia triquetra , Munster, 1838 (in Romer’s paper), Neues Jahrb. fur Min.,&c., p. 384, pi. iii. 
fig. 19. 
., „ Reuss, 1845, Yerstein. Bohm. Kreid., pt. 1, p. 39, pi. xiii. fig. 77. 
,, atlantica, Bailey, 1851, Smithsonian Contrib., vol. ii. art. 3, p. 12, figs. 38-42. 
,, ( Verneuilina ) triquetra, Parker and Jones, 1863, Ann. and Mag. Nat. Hist., ser. 3, 
vol. xi. p. 92. 
The original drawings of this species accompanying Romer’s memoir are very small 
and ill defined, and those given by Reuss some years later are not much more serviceable 
as a means of identification. So far as can be gathered, both authors intended to portray 
an organism with the general contour and structure of that represented in PI. XLVII. 
fig. 19. The precise shape, however, is not of great moment, for the species resembles 
other Textularians in the variability of its external aspect, the same locality furnishing 
long slender specimens like fig. 20, and short pyramidal forms such as that already 
referred to. The test is arenaceous, the exterior generally rugose ; sometimes sponge- 
spicules are used in conjunction with sand as building material, and the angular 
