164 METAMORPHOSES OF MAN 



ists since Chamisso's time, and among others by 

 Eschricht of Copenhagen, who has given us a remark- 

 able anatomical work, in which the very important 

 fact is established, that the chained salpse are united 

 in colonies from the earliest period of their embryonic 

 life.* Unfortunately, Eschricht's observations were 

 confined to specimens preserved in spirit, and the 

 credit of clearing up this history, which was for 

 a long while considered fabulous, is due to two 

 naturalists, the one an Englishman, the other a 

 German. Thanks to the researches of Krohnf and 

 Huxley, J we can now assert that among the biphorge 

 there is an alternation not only of form and of mode 

 of life, but also of mode of reproduction. As the result 

 of their united observations, it may be stated that the 

 compound or aggregated biphorae are hermaphrodite, 

 and deposit eggs only, from which spring isolated 

 biphoras. These latter are neuters, and produce, by 

 internal gemmation only, a series of aggregated 

 biphorae. Here we have, strictly speaking, no strobila, 

 and there is but a single generation of scolices which 

 produce directly a series of proglottides that remain 

 united for the rest of their existence. § 



* " Anatomisk-Physiologiske TIndersoegelser over Salperne," 

 1841. I am acquainted with this work only through various 

 extracts from it, given by other writers. 



f "Memoire sur la Generation et le Developpement des Biphores.' 

 — Annales des Sciences naturelles, 1846. 



J " Observations upon the Anatomy and Physiology of Salpa 

 and Pyrosoma." — Philosophical Transactions, 1851. 



§ It was shown by Eschricht, that the chain salpce are developed 

 upon a sort of stolon situate in the interior of the isolated forms. 

 This might fairly be regarded as a kind of strobila produced by 

 internal gemmation, and concealed within the scolex. 



