go EDWARD POTTS : 



light on the question. It is, in reality, the nearest approach 

 to a realization of the typical gastrula that has yet been 

 found;" and continues in some detail as to the peculiarities 

 of its internal structure. This was written several months 

 after he had carefully watched the living forms and made 

 excellent sections of prepared specimens. Had he lived, my 

 present and previous attempts in this direction would not 

 have been required. 



In the American Naturalist, December, 1885, page 1232 

 (above); same journal, December, 1897, page 1032; in the 

 Quarterly Journal of Microscopic Scic7ice, Volume 50, Part 4, 

 November, 1906, page 623, and in the Proceedings of the 

 Delaware County Institute of Science, Volume II, Number 2, 

 1907, page 77, a brief history of its discovery, appearance 

 and habits at their respective dates, was given. The writer 

 will endeavor to avoid undue repetition by relating in this 

 only such facts as may seem necessary to make clear the 

 more particular life history noticed during the past year. 



HYDJIA VIRIDIS, ETC. 



The now familiar first H\^dra, under its several indifferent 

 specific names, had been known at least since the year 1703 — 

 but in 1744, under the name of the " Zoophyte of Trembley," 

 an interest was created in it among zoologists, only, perhaps, 

 exceeded by that excited amongst natural philosophers, a few 

 years later, by Dr. Franklin's discovery of the identity of 

 lightning and electricity, and in the manj^ experiments devised 

 by him and his correspondents. 



P. H. Gosse writes: " When in 1744 Abraham Trembley, 

 of Geneva, declared what he had seen of this little fresh 

 water animal, this little ball of green jelly, it was regarded as 

 a thing incredible and even impossible." He quotes from 

 "Johnston's British Zoophytes": The facts "were so con- 

 trary to all former experience, and so repugnant to every 

 established notion of animal life, that the scientific world was 



