﻿PROCEEDINGS OF THE 



[Dec, 1856. 



have never seen lashes extending from them. The parenchyma 

 of the body at this stage is composed of two layers of cellular 

 membrane j the outer or epithelial being that which forms also the 

 sheath of the tentacula, the interior that which forms the very con- 

 tractile wall of the digestive cavity and oesophagus. I have also 

 observed at this stage the earliest instance of fissiparious division 

 which lakes place as in Hydra. (See PI. 6, ff. 24 and 26.) From 

 the posterior or stem-end of the bi-tentaculate hydra proceeds a 

 conical diverticulum, (f. 26, f, f,) this soon shows a separation of out- 

 line from that of the original larva, with which it is connected by 

 a short neck. The bud thus formed contains an offset of the main 

 cavity of the original larva, and a short wude communication 

 between the cavities of the two traverses the neck. In a short 

 time, from the prominent circular ridge of the body, are developed 

 two tentacula, as in the original larva, by which time this latter 

 may have acquired four, but there are cases where the develop- 

 ment of the new bud is so rapid that its two tentacula are produced 

 while the original larva is still bi-tentaculate. The number of 

 buds is not limited to one, but is in fact most generally two, and 

 at times I have been led to doubt whether there were not even 

 more than this number, but the maze of tentacula, proboscides 

 and bodies in various stages of advancement, seen through the 

 thickness of the animal's swim-bell, and often against the dense- 

 ly opaque mass of the parent's proboscis, rendered it impos- 

 sible to untie this Gordian knot. At the same time there is an 

 argument against the probability of their being ever more than 

 two buds, in the circumstance that from the peculiar form of the 

 Hydroid before separation, it would be impossible that a greater 

 number than three such forms should be so grouped together, each 

 in such a position as to be able to reach the parent's mouth with 

 its own elongated proboscis, without overlying and overcrowding 

 the others. This may, however, occasionally take place. 



The youngest bud I have figured is the smaller of the two, f. f. 

 in fig. 26, PI. 6. It will be observed that both these buds originate 

 from the posterior or stem-surface, and this is the universal rule 

 from which I have seen no deviation. The buds in this instance 

 are still lozenge-shaped in outline, the proboscis is represented by 

 the free conical blunt projections, which have not yet anything 

 like their subsequent form. It will be noticed also that the original 

 larva from which these hang, is so far advanced that the incipient 

 lobes of the medusa-disk are already considerably developed at g. 



