278 Zoophytes. 



sons of the year, but appear most abundantly about September, Oc- 

 tober and November. Ellis has figured similar excrescences on the 

 G. Abietina, PI. 16 in his ' History of Zoophytes.' These protube- 

 rances, on dissection, prove to be hollow, and to be partly filled with 

 a white granular substance. They are composed of — first, the ex- 

 ternal fleshy bark, with its membrane ; next, the membrane of the 

 axis, which is raised, and in contact with the bark ; then the white 

 granular matter and the denuded axis. 



The next part to be considered is the axis or skeleton, which is the 

 frame-work that gives shape and consistence to the whole. It is 

 homy, solid, elastic and fibrous, and has its centre occupied by a 

 white pith, which extends to all the branches. It varies in size ac- 

 cording to the age of the specimen, but is considerably influenced by 

 the situation in which it grows, being more slender and irregular the 

 nearer it approaches the shore, and the older portions are more solid 

 than the younger. This increase in the size of the axis depends ra- 

 •ther on the integrity of the fleshy bark, than on any action in the part 

 itself, for if, from accident or the incrustation of corallines, the bark 

 be rubbed off", the axis ceases to increase as far as the denudation 

 extends, while all above and below increases as before. The axis, in 

 a transverse section, will be found to be composed of concentric lay- 

 ers, marked by lighter and darker lines, similar to what is observed 

 in the same section of an exogenous stem. The axis of the Gorgo- 

 nia, however, differs from wood in several important particulars, having 

 neither the radiating medullary rays, nor the cellular structure, which 

 renders wood so beautiful an object under the microscope. 



In a longitudinal section, the concentric layers are as apparent as 

 in the transverse. It is longitudinally fibrous, and rends very freely 

 in that direction. In this section, in different parts of the substance 

 of the axis, patches of grey matter are frequently to be found ; most 

 commonly on the lower portions of the trunk, and in the axillae of 

 branches, especially when two rise close to each other. In the bend 

 of the branches it is very common to observe several layers of it 

 formed in regular succession, separated by thin portions of the axis, 

 and in a specimen before me there are five such strata, alternating with 

 the dark fibres of the axis. This appears to be the substance sup- 

 posed by Ellis to be the remains of a portion of the fleshy bark, 

 which had been enclosed between the horny layers by previous denu- 

 dation and regrowth. He says, " we frequently meet with layers of 

 calcareous matter enclosed between circles, which is evidently nothing 

 else but the decayed flesh of the animal, which has been covered and 



