FORAMINIFERA. 889 



bodies and united by a calcareous cement ; they are used also by some 

 Lituolinae. The Trochammine Carterina is unique in forming proper 

 fusiform calcareous spicules which with sand-grains and a calcareous 

 cement make up its Rotaline test. The character of the sea-bottom often 

 influences the composition of the test. Foraminiferal tests are used where 

 Globigerina ooze prevails ; the shells of Radiolaria, frustules of Diatoms 

 where they abound to the exclusion of other material. Ammodiscus 

 incertus, from a bottom of Radiolarian ooze, has a siliceous cement ; 

 Trochammina inflata loses it calcareous cement and becomes chitino- 

 arenaceous when living in brackish water, and in the variety T. macrescens, 

 the test is a flexible membrane with scarcely any calcareous investment. 



As to shape, the Lituolidae are for the most part isomorphous with 

 calcareous Foraminifera ; even Loftusia finds a representative in Alveolina 

 and Parkeria in Keramosphaera. With the exception of some Endo- 

 thyrinae, an extinct sub-family, all are imperforate. The test is sometimes 

 monothalamous, e. g. some species of Rheophax, Thurammina, &c., but more 

 generally polythalamous. The septa are often imperfect in some Littiolinae, 

 e. g. in Lituola they are labyrinthic. The walls of the test in the Loftusinae, 

 e. g. Cyclammina, are thick and cancellated, i. e. traversed by passages, with 

 the exception of a thin superficial layer. Some forms occur both free and 

 adherent ; some are always adherent. Among the latter Webbina, which 

 has either a simple spherical chamber or an oval chamber with a tube, or 

 several oval chambers connected by tubes, has no wall on the attached 

 side. The Astrorhizidae present peculiar types of shape. Psammospkaera 

 is a globe with interstitial apertures here and there, Sorosphaera, a collection 

 of such globes ; in Storthosphaera the orifices are slightly tubulated. 

 Globular or oval forms with a single distinct aperture are seen in Sac- 

 camina, Pelosina, Pilulina, Technitella. The first-named occurs sometimes 

 in groups, the members of which may be connected by tubular stolons. 

 Or the test is a tube closed at one end which may or may not be dilated 

 into a chamber, straight in laculella, sinuous or branched and sometimes 

 adherent in Hyperammina. A simple tube, open at each end, is seen in 

 some species of Astrorhiza^ in Bathysiphon and Marsipella. In Rhabdam* 

 mina there is a central chamber, sometimes scarcely marked, with two or 

 more tubular arms typically radiating from it. This central chamber 

 becomes large, the arms more or less numerous, irregular in shape, and 

 sometimes branching, in some species of Astrorhiza and in Aschemonella ; 

 in the latter several chambers may be connected together irregularly by 

 tubes. Dendrophrya has the chamber adherent, the arms branched, spread- 

 ing or erect. Syringammina consists of a rounded mass of branching 

 sand-tubes, radiating from a common centre and connected at intervals by 

 lateral branches ; the terminal apertures of the tubes are filled with loose 

 sand-grains. The extinct Syringosphaera and Stoliczkaria have a similar 



