890 THE ANIMAL KINGDOM. 



structure. Rhizammina has a free branching tube open at the ends ; 

 so too Sagenella, but the branches anastomose and the test creeps over 

 some foreign object The two genera Botellina and Haliphysema stand by 

 themselves. As to the former, the test is probably attached ; it is more or 

 less straight, expanded, and thin at the free end, where there are inter- 

 stitial apertures ; the rest of the tube is thick-walled and traversed by 

 irregular sandy partitions. Haliphysema has an expanded base from 

 which spring one or more columns, simple or branched, and somewhat 

 swollen at the extremity. 



The protoplasm is typically of a uniform granular character through- 

 out ; but Shepheardella and Lieberkiihnia are said to have a delicate clear 

 superficial layer. Currents in it have been observed in some forms. It is 

 often colourless, but it is brown in many Miliolidae, olive-green in many 

 arenaceous forms from the deep sea, and Orbitolites tenuissima, greenish 

 in O. complanata, reddish or red-brown in 0. duplex, and many others. 

 But the last-named colour is perhaps derived from the food, which consists 

 chiefly of Diatoms *. The pseudopodia are typically fine filaments which 

 branch, anastomose, and extend to a great distance. They show currents 

 of granules flowing outwards and backwards simultaneously in the same 

 pseudopodium. When the test is imperforate they originate as a rule from 

 its aperture alone, whether single, double, or multiple ; in Microgromia 

 and Lieberkiihnia from a pseudopodial peduncle or compact process ex- 

 tended from the mouth of the test. In the Gromidae, except Microgromia, 

 there are also pseudopodia given off from the surface of the test, probably 

 through perforations in it in Diaphoropodon, but in Lieberkiihnia and 

 jGromia itself, where they are plentiful, and Shepheardella, where they are 

 few, from a layer of protoplasm which flows from the aperture round the 

 test Those which radiate from the surface of the test in Diaphoropodon 

 are fine, straight, linear, short ; those which originate from the mass of 

 protoplasm at the mouth of the test form a dense radiant bundle and 

 branch slightly, but if the organism is disturbed some of them become of 

 great length and tufted at several points. The protoplasm in all perforate 

 genera forms a superficial coat from which the pseudopodia are given off, 

 and issues not only from the aperture but the pores of the test, as well 

 as from the interseptal canals when present, a rule to which the genus 

 Lagena is possibly an exception ; L. elegans certainly is so (Biitsckli). In 

 the pelagic Hastigerina Murrayi, and probably in some other pelagic species, 

 this coat is filled with large non-contractile vacuoles, such as are seen in the 



1 The colouring matter exists either in the form of minute particles, or collected in distinct 

 vesicles, but the latter may be symbiotic algae. See p. 894 infra. The oldest chambers are the 

 most intensely coloured, the newest being generally colourless. The colour disappears more or less 

 completely on deprivation of food, and is restored when it is plentiful. The chemical reactions 

 of the reddish colour are like those of Diatomin ; see Max Schultze, ' Organismus,' pp. 19-20. 



