640 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The test is free, porcellanous, spherical, formed of concentric 

 layers, each consisting of a large number of chamberlets arranged 

 more or less regularly in single series. Chamberlets of the same 

 layer communicate with each other by short lateral stolons ; those of 

 the successive layers by the pores which formed the superficial aper- 

 tures of the previous layer. Aperture consisting of numerous pores, 

 one at the margin of each chamberlet. Colour white; surface 

 areolated by the outlines of the somewhat convex chamberlets of the 

 peripheral layer. Diameter about yL inch (2-5 mm.). The specimens 

 were found in material dredged during the ' Challenger ' expedition 

 at a depth of 1950 fathoms, in a locality, roughly speaking, about 

 25° south of the south-western corner of Australia. The material 

 brought up was a nearly white, feathery-looking, diatom-ooze, com- 

 posed chiefly of Diatomacege, Kadiolaria, sponge-spicula, and other 

 siliceous organisms. Foraminifera were not very numerous, about 

 seventeen species in all; and the general aspect of the Ehizopod- 

 fauna was distinctly arctic, except that the calcareous forms were as a 

 rule somewhat thin-shelled. 



Bacterium rubescens Lank.=Monas Okenii Ehr* — L. Olivier 

 considers that he has established that the Bacterium rubescens of Prof. 

 Lankesterf is not a Bacterium, but is in reality Monas Okenii of 

 Ehrenberg. 



The organisms were found by the author in the basins of the 

 Jardin des Plantes at Paris, to which they gave a strong red colour. 

 They were recognized by Prof. Lankester as being Bacterium rubescens. 

 They are of a cylindrical form, slightly compressed towards the 

 middle, and slightly swollen at the extremities. The greater axis 

 measures from • 02 to • 3 mm., the smaller axis • 008 mm. The 

 body is colourless, but contains spherical globules of an intense red. 

 These, instead of being disseminated here and there through the pro- 

 toplasm, are more often arranged in a linear series, following the 

 greater axis. They swim very rapidly, sometimes turning spirally 

 round the greater axis, and progressing in a rectilinear direction. 

 There are two distinct conditions of the organism, the one charac- 

 terized by the great number of the red globules, the frequent division 

 of the body, and the rapidity of the locomotion ; the other by the dis- 

 appearance of the red globules and the slackening of the movements, 

 and of the tendency to transverse segmentation. Every transition, 

 from the first to the second of these stages, and even from the second 

 to the first, is to be found. If we saw the elongated organisms, still 

 active, but not in the condition of division, in a medium rich in nutri- 

 tive substances, such, for instance, as broth sufficiently diluted with 

 water, the little organisms will soon be seen to divide ; and the 

 segmentation may even be so frequent, that it sets in before the body 

 of the animalcule has acquired one-third of the length it attains in 

 circumstances where the segmentation is slower. The number of red 

 globules diminishes in proportion to the activity of the organism. 



* Bull. Soc. Bot. France, xxviii. (1882) pp. 216-26 (1 pi.), 

 t Quart. Journ. Micr. Sci., xvi. 



