SERTULARIA. 203 



gence was six inches by three, computing from the opposite extremities of 

 the parts. 



The stem of the Ramosa is generally very short. It consists of tubuli, 

 of which at least an hundred are aggregated when it is a line in diameter. 

 The central tubuli are almost black ; those towards the circumference are 

 replete with the pith. A transverse section of the stem exposes a kind of 

 porosity resembling what may be discovered in the thin slices of certain 

 species of wood, under the microscope. But the pores are neither of regu- 

 lar figure individually, nor in regular arrangement. — PI. XXXIX. fig. 8. 

 This fasciculated structure, which is very obvious below, disappears above 

 and there the different stalks of the parts resolve into a simple tube. 



The stem of several specimens of the preceding red species, the An- 

 tennina indivisa, which were some inches high, but of smaller diameter, 

 proved a simple thick-sided tube. The aggregate tubuli of the Ramosa, 

 however, are of perfect and independent organization, such as renders each 

 in vigour capable of regenerating new parts. 



On forcible divulsion, the root of this product, i\xe Ramosa, separates 

 as a flat mossy tuft, about half an inch in diameter : but the presence of 

 what is either a mass of foreign matter, or a multitude of short radicles, ob- 

 scures its true formation in the adult state. It is sufficiently evident in 

 an early stage. 



Vegetation. — The regenerative faculty seems more vigorous in this 

 Sertularia than in any of the race, — to which we may possibly ascribe the 

 great embarrassment of observers in determining its distinctive features. 

 Such a property, nevertheless, renders it a favourable subject for physiolo- 

 gical enquiries. 



A group of the green Sertularia ramosa, most narrowly resembles a 

 plantation of pollarded trees in miniature. Dark, aged stems, sustain 

 fine green vigorous reproductions above, of all dimensions and in every 

 stage. 



If the upper portion of an adult be sundered, shoots issue from the 

 tubuli of the stump remaining behind, both from those towards the centre 

 and from others towards the circumference. Great analogy here appears 

 to the vegetable creation. Subsistence of the pith is indispensable to the 



