362 On the Reproductive ^Elements of the Rhizopoda. 



With regard to the male element, I have only one observation 

 to record. Amongst a large number of dark-brown Gromias 

 which I have possessed for many months, one appeared filled as 

 to its upper part with a milky matter, which, when pressed out, 

 proved to be a congeries of cells and lai'ge active molecules, such 

 as are obtained from the sperm-sacs of Hydra viridis. I was not 

 able to make out the tails of the spermatozoa ; but there could 

 be no mistaking the characteristic shape and movements of the 

 cells and molecules. The sarcode of the body in Rhizopods is 

 itself finely molecular in structure, and, when crushed, exhibits 

 shght molecular movements ; but these movements are altogether 

 different from those of the objects which I am persuaded are the 

 spermatozoa of Gromia. 



Since the foregoing paper was sent to the press, I have re- 

 ceived the April Number of the ' Annals,' in which Schultze's 

 discovery of living young in the chambers of Rotalia is brought 

 before the readers of this Journal. Prof. Williamson, in his 

 * Treatise on Recent Foraminifera ' (Ray Soc. Publ.), states, in 

 regard to his Spirillina perforata, "he (Prof. Ehrenberg) assigns 

 to it the trivial name of vivipara, owing to the circumstance 

 that just within the septal orifice of his specimen he found two 

 small spiral shells, which had obviously found their way there 

 by accident : from this unimportant circumstance, he concluded 

 that the shell was viviparous." S. perforata is plentiful in the 

 Firth of Forth, on Fucus serratus. Immediately after reading 

 Schultze's paper, I examined a quantity of the sea-weed, and 

 found two large specimens of S. perforata surrounded by a 

 multitude of very small ones. In one of the large specimens 

 three small living Spirillina existed. Ehrenberg was doubtless 

 right in considering this animal viviparous ; but it remains to 

 be determined whether the young are produced by gemmation 

 or ovulation. In Spirillina foliacea I have found the highly 

 refractive bodies I have above described as " primitive ova." 



55 Northumberland St., Edinburgh, 

 April 17, 1861. 



EXPLANATION OF PLATE XVIIL 



Fiff. 6. Specimen of Truncatulina, decalcified : a, membranous basis of 

 shell; b, sarcode; c, ovum with germinal vesicle and spot; 

 d, segment or zooid destitute of ovum. 



