442 The Apex of the Leaf in Osmunda and lodea. [Mar. 20, 



those -which are solely connected with this convolution. Accordingly 

 it is found that there is a considerable difference in the amount of 

 paralysis for voluntary movement produced in the different muscles, 

 and especially that some of them are found to undergo a considerable 

 amount of recovery in the course of a relatively short time, while 

 others remain permanently and completely paralysed. The paralysis 

 (for volitional impulses) is most pronounced in the muscles of the 

 toes and hind feet, and in the hamstrings and gluteei. The paresis is 

 sufficiently obvious, but less marked in the arm-muscles than in those 

 of the lower limb, while in the trunk-muscles it is extremely difficult 

 to determine what movements are purely voluntary, what are asso- 

 ciated movements, and what are purely reflex movements. We are 

 unable, therefore, to say positively how far the influence of the will 

 over these muscles has been abolished by the establishment of the 

 lesion.* 



It will, therefore, be more advantageous to defer the complete 

 account of the condition of these animals until the opportunity is 

 afforded by post mortem examination of verifying the extent of the 

 lesion and of tracing the resulting secondary degenerations. 



II. " Preliminary Note on the Apex of the Leaf in Osmunda and 

 Todea." (From the Jodrell Laboratory, Royal Gardens, 

 Kew.) By F. 0. Bower, F.L.S. Communicated by W. 

 T. Theselton-Dyer, C.M.G., F.R.S. Received March 7, 

 1884. 



It has long been accepted, in accordance with the investigations of 

 Sadebeck, that there is at the apex of the young leaf of the fern a two- 

 sided, wedge-shaped, apical cell, and that, after this cell has lost its 

 identity by periclinal, and subsequently by anticlinal divisions, the 

 growth of the leaf is continued at the margin by the persistent 

 activity of a linear series of marginal cells. It is true that this is the 

 mode of development of many fern-leaves, but, as my observations 

 show, it does not apply for all cases, while those exceptional cases are 

 particularly interesting as occupying an intermediate position in this, 

 as also in other, respects between the true ferns, on the one hand, and 

 the Marathacece and Cycadece on the other. It is among the Osmun- 



* Since the above was -written we have removed in two other animals the 

 excitable portions of the external surface, in addition to the excitable portion of the 

 marginal convolution. Complete hemiplegia has been the result ; the paralysis 

 affecting not only the muscles of the limbs but also those of the head and neck and 

 of the trunk, whereas in animals in which only the excitable portions of the external 

 surface (the motor regions of Ferrier) have been removed the paralysis is but partial, 

 and confined chiefly to muscles of the limbs. — (Note added March 20, 1884.) 



