DUBLIN NATURAL III8T0BY SOCIBTTT. 109 



On looking into the microscope I was much struck with the peculiar 

 appearance of one of the forms that first presented itself in the field, — a 

 Pleurosigma Spencerii. The usual colour of the endrochrome in this 

 species is pale brown, but in the present instance it was a beauti^l 

 green. A number of granules of a bluish -green colour were distributed 

 through the cell. In a few minutes I observed that the greater portion 

 of the granules, at least two- thirds, moved with a sudden jerk to the 

 lower part of the cell. Some of the granules passed out of the valve, 

 and immediately after an Anthozoid issued from the cell. Shortly after 

 another made its appearance, and another, until six or eight had been 

 extruded. 



All these organisms proceeded in the same manner from the valve, 

 and exhibited themselves in the same spot, within what appeared, under 

 a quarter-inch objective, with No. 2 eye-piece, about V»th of an inch 

 from the extremity of the valve. In form the Anthozoids, if at rest, 

 would have presented very much the appearance of a spike of thistle- 

 down. The head was of a pale green colour, and round it the tail was 

 lashed from side to side with great activity. 



On the same occasion several forms were observed, presenting similar 

 appearances, with Anthozoids moving rapidly about in their immediate 

 neighbourhood. Among these were two or three of the species named 

 CymatopUura solea ; but in no case except the one just alluded to did 

 I observe them issuing from the valve. 



On the evening following that in which the preceding observation 

 was made, I examined a drop from the same gathering, when a great 

 change was noticed to have taken place in the appearance of such ^ato- 

 maceous forms as occurred, compared with that which they presented the 

 evening before. But few granules were seen. The endochrome also 

 had changed its colour 6*om green to olive, and, instead of being diffused 

 through tiie cell, was in many instances collected in a narrow band along 

 each side of the cell, or at the opposite ends of it. In some cases these 

 bands had broken up into isolated portions, and in others the valve was 

 as free from endochrome as if it had been treated with acid. 



The President dwelt on the value of the observation, which was, he 

 believed, perfectly new, and he had no doubt, as such, would be con- 

 troverted, or at least probably received with doubt There was, there- 

 fore, the more necessity for repeating the observation, and, if possible, 

 confirming it. He thought it most probable that these bodies were 

 Zoospores, and not Anthozoids ; though this would not in the least de- 

 tract from the value of the observation. Perhaps Mr. William Archer, 

 who had devoted so much time to the study of the Desmidi® and other 

 simple vegetable forms, would favour them with his views on the 

 subject 



Mr. Archer said that he felt inclined to look on these bodies as Zoo- 

 spores, as suggested by Professor Harvey, otherwise we must suppose 

 that two forms of the same mode of reproduction (that by dissimilar 

 cells) existed among these plants. The observation was, nevertheless, 

 a most valuable one. 



