12 ANDREWS. [Vol. II. 



tJiral co}itiiiuity from cell to cell that is the inediiim of coordina- 

 tion, a)td that is broken by mechanical displacements of the 

 blastomer'es!' 



The nature of this structural continuity was not surmised, 

 but it now seems evident that it is really, in part at least, 

 brought about by such remarkable, changing, pseudopodial 

 threads as were seen in the echinoderms and preserved, in 

 part, in the Amphioxus eggs I had for examination. 



That filose phenomena will be found in the blastula and 

 gastrula stages seems most probable, but as yet I have not 

 been able to find remnants of them in the above-preserved 

 material. The figures published by Klaatsch ^ in illustration 

 of other problems suggest, at first sight, profuse intercellular 

 connections in these stages of Amphioxus, but it seems more 

 probable that the lines there shown are the results of shrinkage 

 and imperfect preservation, though some filose activity may have 

 furnished an element for certain of the distortions that resulted. 



As filose phenomena in eggs as far as yet studied are, to say 

 the least, easily overlooked (in the echinoderms, they can be 

 seen only with difficulty, though the main threads from the 

 polar bodies of Cerebratulus and the above connections in 

 Amphioxus are so distinct as to be readily evident with low 

 powers to one searching for them), we need not expect to find 

 them frequently mentioned in the past literature of embryology. 

 Yet some of them must have been seen, even if passed by as 

 of little moment. Thus Professor Conn described and figured^ 

 fine lines passing out from the surface of the egg of the gephyr- 

 ean worm Thalassemia mellita Conn to the rather distant 

 membrane. These he regarded as striae and interpreted as 

 indicative of the presence of a jelly-like substance between Qgg 

 and membrane. Yet an examination of his Fig. 13, PI. XX, 

 suggests that this Qgg and its polar bodies will prove to possess 

 filose phenomena.^ 



^ " Bemerkungen iiber die Gastrula des Amphioxus," Alorph. Jahrb. Bd. xxv, 

 1897. PI. XII. 



2 Studies from the Biological Laboratory, Johns Hopkins University. Vol. ii. 

 1884. 



3 In correcting proof I add that the connection made by Professor Flemming 

 {Ahrkel and Boiniet, Ergebnisse, 1897, p. 279) between certain fine pseudopodia- 



