Page:Encyclopædia Britannica, Ninth Edition, v. 19.djvu/870

Rh PROTOZOA [RETICULARIA. Genera. Lieberkuhnia, Clap, and Lach. ; Gromia, Duj. (Fig. IX. 2) ; Mikrogromia, Hcrtw. ; Eughipha, Duj. (shell built up of hexagonal siliceous plates) ; Diaphorophodon, Archer (38) (many foreign particles cemented to form shell ; small pseudopodia issue between these, hence resembling 1 erforata, and large long ones from the proper mouth of the shell, Fig. IX. 12). Fam. 2. AMPHlSTOMINA.with an aperture at each end of the shell. Genera. Diplophrys, Barker (Fig. IX. 1); Ditremn, Archer; Amphitrema, Archer (Fig. IX. 11); ShcphcardcUa, Siddall (39) (membranous shell very long and cylindrical so as to be actually tubular, narrowed to a spout at each end, Fig. IX. 3; protopl;i-m extended from either aperture, Fig. IX. 5, and rapidly circulating within the tubular test during life, carrying with it the nucleus which itself exhibits peculiar movements of rotation, Fig. IX. (i 7 8, 9, 10). ORDER 2. ASTRORHIZIDEA, Brady. Chdrudrrs. Test invariably consisting of foreign particles ; it is usually of large size and single-chambered, often branched or radiate with a pseudopodial aperture to each branch, the test often con tinued on to the finer branches of the pseudopodia (Fig. X. 12) ; never symmetrical. All marine. Fam. 1. ASTRORHIZINA, Brad}-. Walls thick, composed of loose sand or mud very slightly cemented. Genera. Astrorhiza, Sandahl (Fig. X. 12, very little enlarged) ; Pdosina, Brady; Storthospheera, Brady ; Dendrophnjn, St. Wright ; Syringammina, Brady. Fam. 2. PILULININA, Test single-chambered ; walls thick, composed chiefly of felted sponge-spicules and fine sand, without calcareous or other cement. Genera. Pilulina, Carpenter; Technitella, Norman ; Batlnj- siphon, Sars. Fam. 3. SACCAMMININA. Chambers nearly spherical ; walls thin, composed of firmly cemented sand grains. Genera. Psammospheera, Schultze; Sorosplue-ra, Brady ; Snrcr/m- mina, M. Sars. Fam. 4. RIIABDAMMININA. Test composed of firmly cemented sand -grains, often with sponge-spicules intermixed; tubular; straight, radiate, branched or irregular ; free or adherent ; with one, two, or more apertures ; rarely segmented. Genera. Jaculdla, Brady; Marsipdla, Norman (Fig. X. 13); Rhabdammina, M. Sars; Asehemonella, Brady; Rhizammina, Brady ; Sagenellci, Brady ; Botdlina, Carp. ; Haliphysema, Bower- bank (test wine-glass-shaped, rarely branched, attached by a disk- like base ; generally beset with sponge-spicules, Fig. X. 11 : pseudo podial aperture, at the free extremity). This and Astrorhiza are the only members of this order in which the living protoplasm has been observed ; in the latter it has the appearance of a yellowish cream, and its microscopic structure is imperfectly unknown (61). In Haliphysema the network of expanded pseudopodia has been observed by Saville Kent as drawn in Fig. X. 11. Lankester (59) discovered numerous vesicular nuclei scattered in the protoplasm (Fig. X. 10, n), and also near the mouth of the shell reproductive bodies (probably bud-spores) embedded in the protoplasm (Fig. X. 8). Haliphysema was described by Bowerbank as a Sponge, and mis taken by Haeckel (60) for a very simple two-cell-layered animal (Enterozoon), to which he assigned the class name of Physemaria. ORDER 3. MILIOLIDEA, Brady. Characters. Test im perforate ; normally calcareous and porcel- lanous, sometimes encrusted with sand ; under starved conditions (e.g., in brackish water) becoming chitinous or chitino-areiiaceous ; at abyssal depths occasionally consisting of a thin homogeneous, imperforate, siliceous film. The test has usually a chambered structure, being divided by septa (each with a hole in it) into a series of loculi which may follow one another in a straight line (Fig. X. 4) or the series may be variously coiled (Fig. X. 1 and 3). The chambering of the test does not express a corresponding cell- segmentation of the protoplasm ; the latter, although growing in volume as the new shell-chambers are formed, remains one continuous cell-unit with many irregularly scattered nuclei (Fig. X. 2). The chambered and septate structure results in this group and in the other orders from the fact that the protoplasm, expanded beyond the last-formed chamber, forms a new test upon itself whilst it, lies and rests upon the surface of the old test. The variations in such a formation are shown in Fig. XII. 1, 2, 3, 4. Fam. 1. NUHKCULARINA. Test free or adherent, taking various irregular asymmetrical forms, with variable aperture or apertures. Genera. Sqiirnnmulirta, Schultze (Fig. X. 9, showing the ex panded pseudopodia) ; Nubecularia, Defrance. Fam. 2. MII.IOI.INA. Shell coiled on an elongated axis, either symmetrically or in a single, plane or inequilaterally ; two cham bers in each convolution. Shell aperture alternately during growth (addition of new chambers) at either end of the shell. Genera. Biloculina, D Orb. ; Fdlntlaria, Defrance; Spirolocu- lina, D Orb. (Fig. X. 1, 2) ; Miliolina, Williamson (Fig. XI.). Fam. 3. HAUERINfNA. Shell dimorphous ; chambers partly milioline, partly spiral or rectilinear. Genera. Arliculina, D Orb.; Vertebralina, D Orb. (Fig X. 4); Ophthalmidium, Kubler; Ifaucrina, D Orb. ; Planispirinff,Segacnze^ Fam. 4. PENEROPLIDINA. Shell planospiral or cyclical, some times crosier-shaped, bilaterally symmetrical. Genera. Cornuspira, Schultze; I eneroplis, Montfort (Fig. X. 3);