192 



NATURAL SCIENCE. 



September, 1896. 



easily recognised on the figure, we see a great number of organs of 

 different nature grouped round the central point of union ; to these 

 Ruedeman gives the general name of central organs. But his work, 

 which is described as " preliminary," does not give us enough infor- 

 mation about these organs. For the present then I would merely 

 remark that a in Ruedeman's Fig. 4 can scarcely be regarded as a 

 gonangium, which means an individual or organ for sexual propa- 

 gation ; but that it ought rather to be considered as an individual 



Fig. 9.— Colonies of Diplograptus (after Ruedemann). 



for sexless propagation, a budding individual. It is of interest to get 

 an explanation of the significance of the hollow virgula, so difficult 

 to understand before. Because of this discovery, we cannot but 

 conclude that all graptoloids were, at least temporarily, connected 

 in this way so as to form parts of colonies of a higher order. This 

 discovery may also give us valuable information as to the mode of 

 life of the Graptoloidea. 



Upsala. Carl Wiman. 



{To he continued.) 



