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THE YOYAGE OF H.M.S. CHALLENGER. 
remains one, Shephear della, in which the test consists of a long, more or less flattened 
cylinder, with an aperture at each end. 
It has been suggested by Claus 1 that certain naked sarcode organisms, with long 
reticulated pseudopodia, Protogenes primordialis and others, classed by Haeckel amongst 
the Monera, are true Rhizopods, and that they have more in common with the Gromidce 
than with the naked Lobose types ( Amcebcea ) — in other words, that they should be 
regarded as Foraminifera without tests. Probably the Biomyxa vagans of Leidy , 2 which 
has been provisionally placed by its discoverer amongst the Gromidce, is an organism of 
the same class. 
The Gromidce inhabit both salt water and fresh ; Gromia oviformis and Gromia 
dujardinii, Lieberkuelmia wageneri, and Shepheardella tceniformis are marine forms 
found amongst the algae of shore-pools or otherwise in shallow water. The Challenger 
collections have yielded no specimens that can with any degree of certainty be assigned 
to the group. One or two examples of a minute, flask-shaped, chitinous Rliizopod, with 
broad phialine neck, have been met with amongst the surface gatherings, but the dead 
tests possess no characters by which their particular affinities can be determined. 
The nearest allies of the Gromidce are to be found amongst the Porcellanea. In 
the Miliolidce, the chitinous test is replaced by calcareous deposit, forming a compact 
imperforate shell ; and it is interesting to note that in brackish water, where the proportion 
of mineral constituents is relatively small, the tests not merely of the Miliolince, but 
also of certain species of arenaceous Foraminifera, are often distinctly chitinous and to 
some extent flexible. There is little except the comparatively larger size of the specimens 
to distinguish some of the Astrorhizidce, which have membranous tests coated with mud 
or loose sand ( Pelosina , for example), from such forms as Diaphoropodon ; and in one 
or two genera of the same group short filose extensions of the sarcode springing from 
the superficial coatings, similar to those which have been noticed in the latter genus, have 
also been observed. 
Family II. MILIOLIDCE, 
The family Miliolidce is coextensive with Dr. Carpenter’s Miliolida, with Yon Reuss’s 
Porenlose Foraminiferen, and with Professor Rupert Jones’s Imperforata vel Porcellana. 
The salient peculiarity of the test throughout the group is accurately characterised by 
the word porcellanous. In the adult condition the typical shell is smooth, even-textured, 
and opaque.-white ; in young specimens, opalescent and translucent ; and whether young 
or old always imperforate. 
Its minute structure, as seen when fragments of very young specimens or thin sections 
of older ones, mounted in Canada balsam, are viewed by transmitted light, is peculiar 
1 Grundziige der Zoologie, 4th ed. (1880), vol. i. p. 172. 
2 Fresh-water Rhizopods of North America, p. 281. 
