and Reproduction of the Polythalamia. 321 



then gradually dispersing) of small granules, which, when de- 

 tached by the hair-pencil and placed under the microscope, 

 proved to be likewise small three-chambered Polythalamia, of 

 exactly the same form and size as those artificially freed from 

 their parent, and only differing from the latter in that in all of 

 them the second chamber already began to show a yellow 

 colour. 



Here, therefore, we have a new proof that Polythalamia bear 

 living young, and that these at the time of their birth are in a 

 comparatively high state of development. This increases our 

 anxiety to know how the Geoponi may propagate, of which 

 Ehrenberg asserts that they carry their eggs about with them 

 in little baskets. 



I have still to observe that I made comparative measure- 

 ments of the chambers of the young animals and the innermost 

 chambers of their parents, and found the measurements to agree 

 perfectly. The first central chamber is perfectly globular, and 

 has a diameter of 0'0112 — 0'0150 Par. line (it varies so much 

 in different individuals) ; the two following chambers are no 

 longer quite globular, and the third is a little larger than the 

 second (the diameter varies between 0*0052 and 0"009 Par. line). 



I have not named the species ; it comes nearest to the Rotalina 

 nitida of Williamson. Large approximated orifices of the shell 

 are wanting. The shell is tolerably opake, and as if composed 

 entirely of small irregular particles — not, indeed, so much as in 

 the Rotalina silicea described by me : the shell also dissolves in 

 acid ; but it is deficient in the liomogeneous, elegant appearance 

 of most other Rotalida. Single large apertures, with jagged 

 rather than sharp round margins, penetrate the somewhat thick 

 shell. 



It could not but be of great interest to examine the state of 

 the mother after the birth. In one case I saw with the lens the 

 shell as if burst in pieces, and on moving it with the pencil I 

 obtained only fragments. In the other case I believed that I 

 saw the shell entire and uninjured. I even transferred it to the 

 object-slide ; but whilst cleaning it from the innumerable little 

 Diatomaccaj adhering to it, it was lost. Nevertheless I con- 

 fidently believe that I recognized yellowish-brown contents in 

 the inner chambers, from which it might be concluded that the 

 whole body of the Rhizopod is not employed in the forma- 

 tion of the young. We shall leave unexpressed all further con- 

 jectures upon the mode in which the reproduction is effected, 

 and conclude with the wish that others may seek the oppor- 

 tunity of making further observations on the propagation of the 

 Polythalamia. 



