SOLITARY SALPS AND CHAIN SALPS sjbj 



out at the other — without lacerating it ! However; on 

 one side of the packing-case-with-the-ends-knocked-out 

 there is a little soft mass of gut and a heart and other 

 tissue, often coloured red or blue. Floating among the- 

 large salps we often find chains of smaller salps, the 

 individuals — twenty or more in number — being joined side 

 by side by means of a distinct band like that of the 

 Siamese twins. These smaller salps may be as big as a 

 hazel-nut, and the chain or row of them is often two feet 

 long. These chains of living creatures look like unclasped 

 necklaces of crystal beads floating in the water. A very 

 interesting fact is that the " chain-salpae " are produced by 

 budding inside the large single salps. One may often 

 find the young chain coiled like a serpent within its 

 parent, and clearly visible through the latter's glass-like 

 body wall. It escapes when grown to a certain . site, and 

 quietly floats away, feeding and growing. But the number 

 of individuals in the chain — from twelve to fifty or more 

 (according to the species) — does not increase after birth, 

 nor do they individually grow to be much more than a 

 quarter of the size of their parent when the chain breaks 

 up and they, too, float for a time as detached individuals; 

 The big solitary salps produce by internal budding 

 these chains of smaller salps^-differing so much in details 

 of shape from themselves as to have received special- 

 names as separate species ; but they do not produce eggs. 

 On the contrary, each of the small individuals constituting 

 a chain of salps produces within it one egg ; and this,' 

 when fertilised, grows within its parent to a fair size, aind 

 is extruded or " born." Then, without passing througlr 

 any " tadpole phase," it increases in size and becomes a 

 solitary big salp, which in due time produces another 

 chain. So that there is an alternation of generations, the" 

 chain-salps producing solitary salps and the solitary salps 

 producing chain-salps. This fact was observed inH' 



