288 
THE VOYAGE OF H.M.S. CHALLENGER. 
It follows, therefore, that, whilst the Lituolida generally are characterised by the 
composite nature of their tests, the precise structure differs sufficiently to furnish 
distinctive characters for the four Sub-families under which they have been arranged, — 
the rough investment being the salient feature of the Lituolina, the smoothly-finished 
test that of the Trochamminina, the thick cancellated walls the peculiarity of the 
Loftusina, and the almost Exclusively calcareous shell that of the Endothyrina. 
In morphological characters the four Sub-families run in parallel rather than 
consecutive lines, and all the more important forms are, to a greater or less degree, 
isomorphous with the prominent types of the hyaline and porcellanous series of 
Foraminifera. 
Thus amongst the Lituolina, the flask-shaped and linear species included in 
the genus Reophax correspond in external form with the perforate genera Lagena 
and Nodosaria ; the partially or completely spiral forms comprised under the term 
Haplophragmium furnish arenaceous parallels, when symmetrical, to Cristellaria and 
Nonionina, when inequilateral, to Rotalia and Globigerina ; the outspread, sandy, 
planospiral type, Coskinolina, resembles in like manner certain modifications of the 
porcellanous genus Peneroplis ; whilst amongst the varieties of Placopsilina may be 
found isomorphs of the adherent Truncatulince. In Haplostiche, Lituola, and Bdelloidina 
the same forms are repeated, but with labyrinthic chambers. 
The morphological sequence of the Trochaminina is very similar. The genus Hormo- 
sina furnishes smooth arenaceous isomorphs of Lagena and Nodosaria, of which Webbina 
is the adherent modification. The spiral Trochammince and the aberrant type Carterina 
follow the same plan of growth as Nonionina and Rotalia ; Thurammina resembles 
Orbulina; and the porcellanous genera Cornuspira and Miliolina find collateral 
representations in the genus Ammodiscus. There appears to be no nearer parallel to 
Hippocrepina than the genus Lagena ; unless indeed the slight transverse constrictions 
of the test are the remains of abortive septation, marking it as an arrested modification 
of a polytkalamous form. 
In the Sub-family Endothyrina, the series is less complete and the relations of the 
individual types are more obscure. Nevertheless, the genus Nodosinella, and in a less 
degree Polyphragma, bear some morphological resemblance to Nodosaria ; and in 
Involutina there is a near approach to the typical conformation of Cornuspira and 
Spirillina. The various species of Endothyra and Bradyina furnish parallels to 
Nonionina and even to Rotalia ; and last of all Stacheia presents varieties approximating 
structurally to Polytrema and Gypsina. 
Of the three generic types assigned to the Loftusina, Cyclammina finds a parallel 
in the porcellanous Peneroplis or in the hyaline Cristellaria, Nonionina, and Nummulites ; 
and Loftusia in the porcellanous Alveolina or the hyaline Fusulina ; whilst Parlceria 
has a porcellanous representative in Keramosphcera. 
