Brackish-water Foraminifera. 287 
chitinous, almost membranous basis. Colour variable, 
usually brown. Aperture large and conspicuous, equal in 
size to the transverse section of the terminal chamber, with 
which it corresponds in form. Length +4 inch. 
In the “ Catalogue of the Recent Foraminifera of Northum- 
berland and am ” (loc. cit.) some specimens of this spe- 
cies, found at Hylton Dene, were described as ^a feeble 
variety of Quinqueloculina, in which the normal, white, porcel- 
laneous shell is replaced by a composite test composed of arena- 
ceous particles imbedded in a chitinous matrix, with but little 
calcareous matter ;” and they are there referred to Q. agglu- 
tinans, D’Orb. Subsequent examination of specimens, obtaine 
m many different localities, of the species originally de- 
scribed by D’Orbigny under that name have led to the con- 
viction that the variety so common in brackish water is quite 
distinct from it. 
8 
acids completely disintegrate, even when they do not entirely 
dissolve, the shell 
light under a power of 200 diameters; b is another portion, 
decalcified by means of strong acid, and mounted in the same 
way. These drawings have been made to show to how small 
