322 ALDEOVANDA VESICULOSA. Chap. XIV. 



taming numerous crustaceans of the genus Cyj)ris, and 

 next morning many were found imprisoned and alive, 

 still swimming about within the closed leaves, but 

 doomed to certain death. 



Directly after reading Prof. Cohn's memoir, I re- 

 ceived through the kindness of Dr. Hooker living 

 plants from Germany. As I can add nothing to Prof. 

 Cohn's excellent description, I will give only two 

 illustrations, one of a whorl of leaves copied from his 

 work, and the other of a leaf pressed flat open, drawn 

 by my son Francis. I will, however, append a few 

 remarks on the differences between this plant and 

 Dionsea. 



Aldrovanda is destitute of roots and floats freely in 

 the water. The leaves are arranged in whorls round 

 the stem. Their broad petioles terminate in from four 

 to six rigid projections,* each tipped with a stiff, 

 short bristle. The bilobed leaf, with the midrib like- 

 •wise tipped with a bristle, stands in the midst of 

 these projections, and is evidently defended by them. 

 The lobes are formed of very delicate tissue, so as to 

 be translucent ; they open, according to Cohn, about 

 as much as the two valves of a living mussel-shell, 

 therefore even less than the lobes of Dion£ea ; and 

 this must make the capture of aquatic animals more 

 easy. The outside of the leaves and the petioles are 

 covered with minute two-armed papillaB, evidently 

 answering to the eight-rayed papillsB of Dionsea. 



Each lobe rather exceeds a semi-circle in convexity, 

 and consists of two very different concentric portions ; 

 the inner and lesser portion, or that next to the midrib. 



* There has been much discus- 1861, p. 146) believes that they 



sion by botanists on the homologi- correspond with the fimbriated 



cal nature of these projections. scale-like bodies found at the 



Dr. Nitschke (' Bot. Zeitung,' bases of the petioles of Drosera. 



