64 ANATOMY AND PHVSIOLOGV OF SALPA AND PYROSOMA 



work, gave the name of Tlialia to some Salpce, which he describes and 

 figures in the rudest manner. 



Bosc seems to have been the first to suspect the identity of these 

 two genera, a suspicion which was converted into a certainty by the 

 researches of Cuvier, who not only disentangled the nomenclature of 

 the genus from the confusion into which it had fallen, but gave the 

 first accurate idea of the anatomy of the Salpce, and first announced 

 their true zoological relations. 



69. Much was added piecemeal to the foundation thus laid by 

 Cuvier, by subsequent authors. Meyen and Milne-Edwards described 

 the nervous system, Kuhl and Von Hasselt, Eschscholtz and Milne- 

 Edwards, announced the singular nature of the circulation. Cuvier 

 and Chamisso hinted, and Meyen described, the placental connec- 

 tion of the solitary foetus with the parent ; Eschricht and Sars 

 declared the proximate nature and mode of origin of the Salpa chain. 



70. Chamisso again founded the theory of the " alternation of gen- 

 erations," using that very phrase^ to express the peculiarities accurately 

 observed by him in the mode of multiplication of the Salpce, but the 

 nature and existence of the sexual organs remained undetermined 

 until Krohn and Steenstrup in 1846 discovered the male organs ; sub- 

 sequently Krohn made out the true ovaries also. 



Finally a most accurate account (to which indeed the present 

 memoir can be considered only as confirmatory independent testi- 

 mony) of the whole course of development and reproduction of the 

 Salpce was given by Krohn in the Annales des Sciences for 1846. 



71. Without undertaking the somewhat unprofitable task of giving 



' Justice seems to have been hardly done to Chamisso as the first promulgator of the theory 

 of the " alternation of generations." He says at p. 10, " Qua seposita (Salpa bicorni) alter- 

 nationem generalioniiiii legem esse ut posuimus genericum, omnibus communem speciebus, 

 olKervationibus innititur ; " and at p. 3, " Talis speciei metamorphosis generationibus in 

 Salpis duabus successivis perficitur, forfiia per ^enerationes ( neqtiaqiiain in frole sett in- 

 dividuo) tiiulala, \'eruiii enimvero qua lege proles Salparum, ut animal ab ovo, imago a 

 larva, inter se differunt, jiarum elucet." And in his interesting " Reise um die Erde," 

 Chamisso shows still more clearly his distinct conception of the theory by the remarkable 

 phrase, " Es ist als gebare die Raupe den Schmetterling vmd der Schmetterling hinwiederum 

 die Raupe." " It is as if the Caterpillar brought forth the Butterfly, and the Butterfly the 

 Caterpillar." 



Subsequent writers seem not to have done much more in reality than bring new cases 

 under the law here so clearly expressed, and they do not always seem to have kept so clearly 

 in mind the modest renunciation of any claim on the part of the theory to be an explanation 

 of the facts contained in the last paragraph of the former quotation. 



Finally, it must not be forgotten, that though Chamisso was the first promulgator of the 

 "alternation," he expressly (with a candour impossible to be too much commended) gives 

 the credit of the conception to his companion Eschscholtz, " generationis Salparum primus et 

 perspicax fuit indagator amicissimus Eschscholtz," p. 9, and again in the preface to the second 

 fasciculus of his observations. 



