280 Zoophytes. 



being the first part formed. Branches are formed indiscriminately on 

 all parts of the axis, but most abundantly on the newest. Their mode 

 of formation can be best observed in a longitudinal section. The re- 

 sults of numerous such sections are, that the first visible part formed 

 is a white speck near the centre of the axis, separated from the pith 

 by the interposition of several layers of the axis. This speck is 

 at first very small, but it soon increases in size, and becomes triangu- 

 lar, having its base towards the pith, and apex towards the circum- 

 ference of the axis. The apex, at first, is removed from the circum- 

 ference of the trunk or branch by full two-thirds of its semi-diameter, 

 but as it increases in size the intervening layers gradually disappear. 

 At length the apex of the pith reaches the circumference, and the in- 

 vesting membrane, with the surface of the axis, becomes elevated 

 into a small sharply-pointed eminence. This forms the first external 

 appearance of a branch, and is observable only when the bark is ta- 

 ken off; having once become prominent, it increases and grows like 

 the older branches. How the first nucleus is formed I have never 

 been able to determine, but it seems most probable from a process 

 going on in the axis itself; it certainly has no connexion with the 

 presence of the grey enclosed matter mentioned above. This nu- 

 cleus for the branches very closely resembles the pith, both in con- 

 sistence and whiteness, while the other matter has a yellowish tinge. 

 In a longitudinal section of seventeen specimens, the pith of all the 

 branches bore the same relative situation to the pith of the trunk, and 

 the triangular pith of such branches as had just reached the surface 

 was exactly the same : it is not at all difficult to trace this pith from 

 the branch to the mere speck. The rudimentary pith can therefore 

 be readily distinguished from the other grey matter, first by its situa- 

 tion, then by its colour and shape, and, in addition to these, it may 

 be noticed that the layers of the axis are always closely in contact 

 with the young pith, while with the grey matter there is generally a 

 vacancy between it and the surrounding axis. The axis thus seems 

 to have an action going on within itself, entirely inconsistent with an 

 inorganic character. 



The specimens of this species which grow off our headlands, and 

 in situations where they are liable to be disturbed with a variety 

 of currents, become very bushy and irregular in their growth. Their 

 branches, which are long and cross each other, frequently get denuded 

 of a portion of their bark, and most probably by friction. When this 

 occms, the branches, at their points of crossing, become firmly united 

 to each other, and, in some cases, for half an inch in extent. On 



