Brackish-water Foraminifera. 291 
branous, subarenaceous, scarcely caleareous. Colour brown. 
ng diameter =}; inch. 
That the thin outspread nautiloid Trochammine which 
abound in some localities are the result of depauperating exter- 
nal influences, possibly extended through very many genera- 
tions, is most probable, the only alternative supposition being 
that they are passage forms between the chitinous and arena- . 
ceous groups of Rhizopoda. Accepting the former view, the 
difficulty remains whether the complanate specimens approxi- 
mate most nearly to Lituola canariensis or Trochammina in- 
Jata, if, indeed, these two are not the same species. The pre- 
ference for associating them with Tv. inflata is founded rather 
on the extreme tenuity of the test, its membranous nature, and 
its agreement in chemical relations, than on morphological pe- 
culiarities. Supposing the connexion with Tr. inflata to be 
such as has been indicated, there is a manifest convenience in 
distinguishing the variety by name in the same way as the 
starved conditions of other genera are recognized. The che- 
mical characters of the test have been before described. The 
concavity of the individual chambers is due in great degree to 
the falling-in of the walls from the contraction of the sarcode 
in drying; but in some specimens with thin square edge, and 
having a general contour not unlike limbate Operculine, ap- 
pearances are against the supposition that the segments ever 
were convex. 
Lituola scorpiurus, Montfort, sp. 
Reophax scorpiurus, Montfort (1808), Conchyl Syst. vol i. p. 330, 
83e genre. j 
A single specimen only, and that of the stunted form with 
obscure septation which alone appears on the east coast. It 
was found in the scarcely brackish material from the Forth. 
Lituola canariensis, D'Orbigny, sp. 
Nonionina canariensis, D'Orbigny (1839), Nat. Hist. Canaries, p. 128, pl. 2. 
figs. 33, 34. 
Not uncommon in the more marine localities ; In the areas 
most influenced by the influx of fresh water it often gives 
place to Trochammina macrescens. 
Lagena sulcata, Walker & Jacob. 
Serpula (Lagena) sulcata, Walker & Jacob (fide Kanmacher) (1794), 
Adams's Essays on the Microscope, 2nd ed. p. 634, pl. 14. fig. 5. 
This, the typical form of Lagena, is also the commonest in 
brackish water. Its absence is Me ei in the estua- 
rian pools of the Tay, Tyne, Wear, Tees, — and. in 
