112 



which the excessively delicate central chambers of the test are 

 preserved from destruction in the mechanical process ; the second, 

 an ingenious contrivance of Mons. F. Schaudinn, assistant at the 

 Zoological Institute of Berlin, by which Foraminifera can be 

 placed under observation throughout all the phases of their 

 ■existence. 



As far back as 1841, Ehrenberg noticed a Spirillina with a 

 great number of young examples within the chambers of the 

 parent shell, and as the observation was unique he conferred upon 

 it the trivial name of vivipara. Similar phenomena were sub- 

 sequently seen by Schultz and other observers in individuals 

 belonging to several different genera. In 1861 Mr. Carter 

 •detected the existence of spherules in the chambers of some fossil 

 Foraminifera, which he regarded as " propagative agents." * 

 About the same time attention became directed to the structure 

 of the sarcode or protoplasm that formed the living body of the 

 animal, and in 1878 A. .Schneider published f the results of his 

 researches with regard to the reproductive processes pertaining 

 to the genus Miliolina. The most striking point of Schneider's 

 researches was, that in some instances the protoplasmic body 

 became broken up into two kinds of minute bodies, the smaller 

 of these, possessing spontaneous movement, he regarded in the 

 light of spermatozoa, and the larger as ova. The latter developed 

 into young Miliolina, and after secreting a delicate calcareous 

 test passed into a free condition. These observations of Schneider 

 require confirmation. The first definite step in elucidating the 

 life history of the Foraminifera was taken, however, in 1880, 

 when Munier-Chalmas, the distinguished French microscopist, 

 announced that in the case of certain species of Nummulites and 

 Assilina the initial chambers were formed on two distinct plans. 

 In the one case the primordial chamber was large, and in the 

 •other the same primordial space was occupied by a number of 

 small chambers. Thus the individuals of a species were divided 

 into two natural groups (1) those which had a megalospheric 

 central chamber, and (2) those with a microspheric centre. The 

 external features of the two groups were identical, except that 

 those individuals which had the large central chambers were, in 

 most species, smaller in size than those which had the smaller but 

 more numerous central chambers. This " dimorphism," as it was 

 ■called by Munier-Chalmas, has been made the subject of careful 

 and systematic investigation by the last-named eminent savant 

 in conduction with the able and energetic specialist, Charles 



* Ann. Mag., Nat. His. Ser. 3, Vol. VIII. , 1861, p. 309. 

 t Beitrage zur Kenntniss der Protozoen. Zeits. f. Wiss., Zool., Vol. 30, 

 Sup. 1878, p. 446. 



