274 Mr. Griffith on the Ambmsinia ciliuta nf Ruxhurgh. 



necessity. The separation in question appears to depend upon some constric- 

 tion exerted upon the cotyledon by the apex of the nucleus. 



The immense development of the plumula is the cause of the obliquity of 

 the radicle, and appears to be intended to obviate the effect of the separation 

 of the cotyledon : it is one among- many instances of adaptation to correct 

 what would otherwise be a destructive or fatal anomaly. 



The fact of the presence of stomata on the processes of this body is extra- 

 ordinary enough, particularly when it is recollected that they exist in fruits 

 which have ripened under water. 



Nothing can prove more satisfactorily than the present instance the abso- 

 lute necessity of tracing anomalous forms back to the earliest periods of their 

 development. In this case the process is attended with the desired effect, viz. 

 of reducing the anomalies to the ordinary type of formation. It is very evi- 

 dent that the form of the embryo, immediately before its conical apex projects 

 through that of the nucleus, closely resembles the usual form of these organs 

 in other Aroideoe, since we have a superior I'adicle, a cotyledon, and a tendency 

 to the formation of a lateral slit, as indicated by the depressed areola. 



EXPLANATION OF THE PLATES. 

 Tab. X. 



Fig. 1. Spatha of Cryptocoryne ciliata, cut through longitudinally, representing the spadix 

 in situ and half of the septum. 



Fig. 2. Spadix about the time of impregnation, and after the disappearance of the coniform 

 membrane of the anthers. 



Fig. 3. Vertical view of a pair of anthers. 



Fig. 4. Theca of anther fully formed, viewed obliquely. The opening in the apex of the 

 projecting membrane is very distinct, and through it is seen passing a grumous 

 ioyaw-looking body of great length. 



Fig. 5. Longitudinal section of one theca, showing the arrangement of its fibrous cells, and 

 the perforation of the apex of the projecting portion of the lining membrane. 



Fig. 6. Vertical view of a theca, about the period of impregnation, and after the disappear- 

 ance of the coniform projection. The pollen is seen exposed. 



