REPORT ON THE FORAMINIFERA. 
569 
seven visible segments which are individually much inflated, and the sutures 
correspondingly depressed externally ; whilst the latter, Polymorphina communis, has 
only four or five visible segments, of which the sutures are excavated in a less degree. 
These characters, however, are soon found to be the result of mere individual peculiarity, 
and beyond that to have little or no distinctive value. 
In the “ Vienna Basin ” memoir both forms are included, and the terms in which they 
are described are so nearly alike as to be practically useless for the identification of 
specimens. It may be inferred, however, that the shell of Polymorphina communis is of 
smaller size, that the superior end is acuminate (the oral extremity of Polymorphina 
prohlema being obtuse), and that the sutures are complanate — none of which are very 
noteworthy distinctions. 
Reuss, in his notes on Herr von Schlicht’s Septaria-clay Foraminifera, one of the 
lamented author’s latest contributions to the literature of the Rhizopoda, treated Poly- 
morphina communis as a variety of Polymorphina problemci. 
Practically it is quite impossible, with a number of specimens under examination, to 
say by any rule how they should be apportioned between the two “ species,” and under 
these circumstances the recognition of both appears needless complication of the 
nomenclature. Polymorphina problema, which obviously represents the more fully 
developed form, might with advantage be adopted as the type of the group, and the term 
“ communis ” allowed to lapse. 
In like manner the two forms are closely associated in their distribution, which 
either from a geographical, bathymetrical, or a geological point of view, affords no basis 
for separate treatment. They are found in the littoral, laminarian, coralline, and coral 
zones of almost every latitude, reaching as far north as lat. 79° 26' N., and southwards at 
any rate to Tristan da Cunha and the Cape of Good Hope. The greatest depth at which 
they have been observed is 155 fathoms. 
The same varieties are recorded from the Lower Lias (Blake) ; they are also well 
represented in the Chalk, and in marine formations of almost every later geological age. 
Polymorphina ohlonga, d’Orbigny (PL LXX1II. figs. 2-4). 
Polymorphina ohlonga, d’Orbigny, 1846, For. Foss. Vien., p. 232, pi. xii. figs. 29-31. 
,, uvv&formis, Reuss, 1855, Zeitsclir. d. deutsch. geol. Geselkch., vol. vii. p. 289, 
fig. 5. 
„ guttata, Id. 1870, Sitzungsb. d. k. Akad. Wiss. Wien, vol. lxii. p. 487. — 
Schlicbt, 1870, Foram. Pietzpuhl, pi. xxx. figs. 25-32. 
This is an elongate variety, with characters intermediate between those of Polymorphina 
problema and Polymorphina compressa. The test is morn or less compressed, and has 
six to eight visible segments, which are somewhat oblong and inflated in contour, and 
