412 PEOF. ALLMAK ON THE RECENT RESEARCHES 



Hertwig noticed on tbe walls of the jars containing living speci- 

 mens of Botalia little heaps of from twenty to forty small 3- 

 chambered individuals which were united to one another by their 

 protoplasm, and in each of which he succeeded in demonstrating a 

 single nucleus. Max Schultze had shown that in some other 

 genera the young are not only developed within the shell of the 

 maternal animal, but become invested with their own shell before 

 leaving the parent ; and it is highly probable that these little colo- 

 nies of young Rotalia have a similar origin. 



Prom what is thus known of the reproduction of the Forami- 

 nifera, we may conclude that the protoplasmic body of the parent 

 breaks up into segments, conditioned by the nuclei which had been 

 developed in it, while each of these segments forms for itself 

 within the maternal shell its own investment. In Botalia they 

 would seem to become free by the destruction of the parent shell 

 and then to live for a time in union with one another. 



The discovery of a nucleus in the Foraminifera will now deter- 

 mine the place which we must assign to them among sarcode 

 organisms ; and F. E. Schulze has accordingly attempted by 

 means of a hypothetical genealogical tree to express the descent 

 and mutual affinity of all the leading groups of the E-hizopoda. He 

 employs this designation in a wider sense than has been accepted 

 by many recent zoologists, and embraces under it all those low 

 organisms which, during the greater part of their lives, and espe- 

 cially during the period of their highest development, are brought 

 into relation with the external world by means of pseudopodia, 

 which they employ for locomotion and for the prehension of nu- 

 triment. All these organisms agree essentially with one another 

 and constitute a definite group, whether a nucleus be differentiated 

 or not, whether pulsatile vacuoles or hard parts be present or absent, 

 or whether the pseudopodia present the condition of broad lobes, of 

 fine filaments, of a complex network, or of any other modification. 



The base of the tree where its stem is as yet undivided con- 

 sists of the primitive forms — mere non-nucleated cytodes — repre- 

 sented by Haeckel's Monera {Protamoeba, Protogenes, Protomyxa, 

 Myxodictium, &c.). From these, by the differentiation of a nucleus 

 in their protoplasm, are evolved the nucleated forms (Amceha, 

 freshwater MonotJialamia, Foraminifera, Seliozoa, &c.) which 

 constitute the subdivisions into which the stem branches off. 

 These repeat the various modifications of pseudopodia (lobose, 



