86 ZOOPHYTES. 



gemmation soon ceasing, except in certain shoots, at still longer inter- 

 vals, which continue growing and lengthen out into large branches. 

 This principle admits of some irregularity, arising from an unequal 

 amount of nourishment, or a difference of exposure, but in general 

 there is a remarkable uniformity. And it is due to this fact, that 

 species have their specific characters displayed in their modes of 

 branching; that some species spread widely, with long even branches, 

 and others, with numerous crowded ramifications ; and, moreover, the 

 individuals of a species are alike in their general forms. 



This principle determines the distance of a lateral polyp from the 

 apex of a branch, before it can commence to bud, as well as the dis- 

 tance separating branches. The Gorgonia setosa, the subject of our 

 illustrations, in 74, is a beautiful exemplification of this subject, and 

 well merits farther remark. In this species, the lateral polyps rarely 

 bud and form branchlets nearer than six to nine inches from the 

 apex, eight inches is the average distance, and, as there are about 

 eighty polyps on the lateral surface to an inch in length, it follows, 

 that generally more than six hundred polyps are situated above the 

 first branchlet. And, moreover, as the branchlets are about a third 

 of an inch apart on each side, polyps enough are added, by budding, 

 to lengthen the apex correspondingly before another side-polyp buds, 

 and another branchlet starts. 



What is here indicated, but that the process of budding exerts an 

 inductive influence for some distance from the centre of action, that 

 there is a concentration of nutriment and offerees required, measured 

 by the interval between the budding centres? In the Gorgonia, just 

 alluded to, some hundreds of polyps are thus, in one sense, tributary to 

 the budding polyps at the extremity; for, until the budding apex has 

 grown beyond to a certain distance, one of the side-polyps, though 

 ready to bud, cannot summon gemmating force enough to develope 

 buds ; but when the former is so far removed, that the required 

 nutriment and vital force are supplied, then the excess, which goes 

 on increasing, concentrates upon one of the side-polyps below. The 

 lateral polyp, which becomes a new centre of gemmation, is a 

 certain distance above the preceding branchlet, owing to the fact, 

 that this branchlet exerts its influence for a short distance around 

 itself, though already considerably elongated. The same principle is 

 illustrated even in the irregularities or apparent exceptions. When 

 side branches form low on the stem, the intervals are often much 

 larger than above stated, owing to the less amount of nutriment 



