Prof. C. Morren on the Morphology of the Ascidia. 413 



another cone, which disclosed the organs of fecundation, I 

 could not help comparing it to a large moss armed with its 

 calyptra. 



In Nepenthes and Sarracenia the ascidia also are at first 

 shut up, and at Edinburgh, upon the beautiful plants of 

 Nepenthes, cultivated with so much skill by Mr. MacNab, I 

 was able to learn how their dehiscence takes place. The part 

 which the circular struma acts, with its numerous small trans- 

 verse ribs, then becomes very easy to understand. Before 

 the operculum is detached its thin margins are folded round 

 this struma, which holds them very strongly fixed, as a bladder 

 is fastened over the opening of a vessel by the inflected margin. 



When once the. operculum is freed it cannot again fasten 

 itself above the struma. This dehiscence of the lid is therefore 

 horizontal or in a small degree oblique, like the direction of the 

 struma itself, and it is nearly the same in all ascidia. On that 

 of the tulip formed by monstrosity, the opening, although in 

 this case it was an actual rupture caused by internal violence, 

 took place notwithstanding in the same manner. This com- 

 parison deserves some attention, especially if further observa- 

 tions tend to confirm it. 



The other accidental ascidium which I had the pleasure of 

 seeing among the preparations of the Rev. Mr. Hincks, was 

 of a kind altogether singular. It belonged to the Polygonatum 

 multiflorum ; but it had not shown itself like that which I had 

 myself gathered upon the same species of plant, at the upper 

 part of the plant, but at the lower part of it. It was an en- 

 casing of three ascidia one in the other, through the centre 

 of which passed the stalk, which when once free above them had 

 become covered with its usual leaves and flowers in their nor- 

 mal form. Imagine therefore a foliaceous pitcher ending in 

 two lateral and opposite auricles, serving as a case to two other 

 pitchers which also have two opposite auricles, and above them 

 a bunch of leaves and flowers, and we shall have a represen- 

 tation of this beautiful monstrosity, of this curious anomaly. 

 Here again the outer surfaces of the ascidia were the under 

 surfaces of the leaves, so that this condition never contradicts 

 itself, and thus it acquires the value of a well-established law. 

 It is always the carpellary state which is repeated, the floral 



