312 
NOTES AND MEMORANDA. 
Figs. 1 to 16 represent zooicls seen more or less nearly in profile ; 
Figs. 17 to 20, zooids seen from above. Figs. 5, 6, 8, 14, 15, were 
drawn by Mr. Goode; the remainder by tbe writer. The drawings 
testify to the entire agreement between the two observers. The 
zooids seen by us appear to have been of the mouthless kind. 
Moseley has noticed the fact that these expand much more readily 
than the others. Our observations were made partly with a 2-inch, 
but chiefly with a 1-ineh objective. 
cQd Q? £3 
16. 17. 18. 19. 20. 
Some attempts were made to study the zooids by means of decalcified 
specimens, previously treated with picric acid and alcohol ; a j^re- 
liminary treatment with picric acid and subsequent removal to 
alcohol having been shown by experiments undertaken by members of 
the United States Fish Commission in 1874, to be remarkably 
eftective in preserving the delicate tissues of Hydrozoa. We did not 
succeed in obtaining by this means any zooids in satisfactory con- 
dition. The specimens, however, prepared as above stated, and 
subsequently mounted in glycerine jelly, show well some details of 
structure, particularly the lasso-cells with extraordinarily long threads, 
figured by Moseley.* Moseley’s figures of a lasso-cell from 31illepora 
nodosa illustrates well the character of those in Millepora alcicornis, 
though in the latter the spinous portion is somewhat nearer the base 
of the thread. The length of the thread in the largest of our speci- 
mens is about * 027 inch.j 
Liberation of the Zoospores, Anther ozoids, dc., in the Loiver Plants. 
— M. Cornu has succeeded in producing at will the emission of the 
antherozoids of Polijstichium Filix~Mas, of which the prothallia had 
been kept at the surrounding temperature during the cold season. In 
March, one of the prothallia, having been removed and placed in a 
drop of the liquid from the same flask, to be examined under the 
microscope, emitted a great number of agile antherozoids ; the same 
thing happened in June. Nothing was changed in the conditions of 
* ‘Phil. Trans.,’ clxvii. pi. ii. fig. 1. 
t Mr. Wm. North Rice, in ‘American Journal of Science and Arts,’ vol. xvi. 
p. 180. 
