450 



vorigen Jahres trocken gelegen hatte und die Schlamm portion am 

 14. Februar dieses Jahres entnommen wurde. 



Bereits nach circa zehn Tagen zeigten sich an den Glaswänden 

 reichlich Harpacticiden — und nur solche — , welche ausnahmslos der 

 mehr erwähnten Species angehörten und fast alle in Copula betroffen 

 wurden. Die nach so kurzer Zeit erscheinenden Copepoden hatten 

 somit eine den ganzen Winter überdauernde Periode der Trockenstarre, 

 wie Zach arias diesen Zustand irgendwo ganz zutreffend bezeichnet, 

 durchgemacht. 



München, im October 1899. 



5. A new Function of the Vascular ampullae in the Botryllidae^ 



By Frank W. Bancroft, Parker, Fellow of Harvard University, U. S. A. 



(With 2 figs.) 



eingeg. 25. October 1899. 



The colonial vessels of the Botryllidae are, as has long been known, 

 purely ectodermic structures, and end in large numbers of terminal 

 enlargements — the ampullae. These are found nearly everywhere 

 within the colony, but are situated principally along the edges, which 

 they often line several rows deep. Many functions have been attributed 

 to them. The early authors considered them buds that developed into 

 the zoöids of the colony (Giard '72), but since this was disproved by 

 Metschnikoff ('69) the blastogenic function of the ampullae has 

 been generally given up. Herdman ('86 p. 25) however believes 

 that, in Sarcohotrylloides Wyvilln at any rate, buds are formed by the 

 ampullae; and Giard ('91) still thinks that the inability of these 

 structures to produce new zoöids has not been sufficiently demonstra- 

 ted. At present most authors consider the ampullae purely ectodermic 

 structures having nothing to do with reproduction and acting as sto- 

 rage reservoirs for blood, organs for the secretion of the test matrix 

 (Oka '92, p. 524) and respiration (Herdman '84). In these three 

 respects the ampullae undoubtedly perform important functions, and 

 I have still another to add to the list of their activities; namely that of 

 blood propulsion. 



It seemed probable that if, as Herdman and Giard maintain, 

 the ampullae are capable of producing new individuals, severing them 



1 This investigation was begun at the U. S. Fish Commission Laboratory at 

 Wood's Hole in 1898, and finished at Naples in 1899. So far as I could see there 

 were no differences in the behavior of the Botryllu s colonies from the two places. 

 I wish to express my thanks to the Fish Commission for the facilities enjoyed in its 

 laboratory, and also to the Smithsonian Institution whose table I occupied at the 

 Zoological Station in Naples. 



