234 SOLITARY AND CHAINED 



together in long chains, composed of many similar 

 individuals. These chains glide through the waters 

 with a regular serpentine movement, as if a common 

 will influenced them; and yet every animal of the 

 chain is a distinct individual, and capable of a separate 

 existence, if the rules of the brotherhood be dissolved. 

 While swimming in the water, the chain appears like a 

 single animal ; but when taken up it falls to pieces, and 

 the animals of which it is composed have no further 

 power to unite : yet they can continue to exist. But 

 this is not the wonderful part of their history. The 

 strange fact connected with them is this, that the ani- 

 mals chained together only represent one phase ofSalpa 

 life. There are other individuals, of the same species, 

 but of a very different form, which have never been 

 united in chains, but have at all times lived solitary. 

 And still more strange, these solitary Salpae are the 

 young (7f Salpce that have been chained ; and the pro- 

 geny of these solitary ones will be chained Salpce. Nay, 

 it has been ascertained to be an invariable fact that the 

 ovum of one of the chained Salpos produces a solitary 

 animal, while the ovum of a solitary Salpa produces a 

 chain. Or, as Chamisso, who first observed this pecu- 

 liarity, graphically says, " A $a^:>a-mother is not like 

 its daughter, or its own mother, but resembles its 

 sister, its grand-daughter, and its grand-mother." 

 Our figure, copied from Professor E. Forbes, represents 

 both states of the only recorded British species. 



In Steenstrup's Memoir, already alluded to, the vari- 

 ous aspects of these alternate developments have been 

 ably discussed ; and the Author has, I think, clearly 



