VII 



OBSERVATIONS UPON THE ANATOMY 

 AND PHYSIOLOGY OF SALPA AND PYROSOMA 



Philosophical Transactions of the Royal Society, 1851,/A ii. pp. 567-594; also- 

 in Annals and Magazine of Natural History, vol. ix. 1852,//. 242-244 



1. The SalpcE, those strange gelatinous animals, through masses of 

 which the voyager in the great ocean sometimes sails day after day 

 have been the subject of great controversy since the time of the pub- 

 lication of the celebrated work of Chamisso, De Animalibus quihisdam 

 e classe Vermium Linnceatia. 



In this work were set forth, for the first time, the singular pheno- 

 mena presented by the reproductive processes of these animals, — 

 phenomena so strange, and so utterly unlike anything then known to 

 occur in the whole province of zoology, that Chamisso's admirably 

 clear and truthful account was received with almost as much distrust 

 as if he had announced the existence of a veritable Peter Schlemihl. 



In later days an opposite fate has fallen upon the statements in 

 question. They have been made the keystone of a revived ^ theory, 

 and the phenomena presented by the SalpcE have been cited as 

 "glaring instances" of a law governing the vast majority of the lower 

 invertebrata — the law of the " Alternation of Generations." 



2. There appeared then to be two main points to be kept in view in 

 examining the Salpcc : — 1st. Are the statements made by Chamisso 

 correct? and 2ndly, if they be correct, how far is the "alternation 

 theory" a just and sufficient generalization of the phenomena? 



3. These questions, however, could not be entered upon without a 

 thorough preliminary study of the structure of the Salpce, the oppor- 

 tunities for which are granted but to few. 



Such opportunities were afforded to the writer of the present paper 

 at Cape York, in November 1 849 : for a time the sea was absolutely 



' Not new, see (70). 



