62 ■ HISTORY. 



prepared the -way for a systematic arrangement ; but, as yet, the Polyzoa of fresh water had 

 been placed in the same genera with marine forms of a totally diiferent organization, while 

 some of them had not been accurately distinguished from one another. 



At length, Cuvier, in his ' Tableau elementaire des Animaux,'* struck by the distinctive 

 characters of the little Polyzoon described by Rosel, under the name of " Der Kleinere 

 Federbusch -polyp mit dem ballen-formigen Kcirper," assumed it as the type of a new genus, 

 to which he gave the name of Cristatella. The other fresh-water Polyzoa he allowed to 

 remain in the genera in which his predecessors had placed them, and even with regard to his 

 Cristatella, though he acknowledge its affinity with the other fresh-water Polyzoa, he was 

 ignorant of its true relations, for he kept it in the vicinity of the infusorial Vorticella. 



In the year 1804, Vaucher published, in the ' Bulletin de la Societe Philomathique,' a 

 short description of two Polyzoa, one of which he believes to be the animal described by 

 Schaflfer [Tvhidaria repens, Midler); the other a new species to which he gives the name of 

 Tuhidaria lucifuga.\ Vaucher's memoir is accompanied by figures of both species, but the 

 description is so meager, and the figures so defective, that it is impossible to determine the 

 species intended. 



The memoir of Vaucher was followed by a most important reform. Bosc, already con- 

 vinced, that the so-called Tuhularias of fresh water were incorrectly associated with the 

 marine group of this name,J now constituted for their reception a distinct genus, whose 

 characters he gave in the same number of the ' Bulletin ' as that which contained Vaucher's 

 memoir. The following are the characters on which Bosc founded his new genus : 



" Polyi^ier fixe a tige grele, membraueux, souvent ramifie, termine, ainsi que ses rameaux 

 par uu polype dont le corps peut entrer entierement dans la tige, et dont la bouche est entouree 

 d'un seul rang de tentacules cilies." 



Bosc, however, though he defined the genus, neglected to name it, and his views received 

 but little attention till Lamarck, in his ' Histoire des Animaux sans Vertebres,' published in 

 1816, gave the name oi PhimateUa to the genus defined by Bosc ; while, for the Alcyonium 

 jiuviatile of Bruguiere, he constituted a new genus under the name of Alcyonella. In 

 his definition of the genus Alci/onella, Lamarck has evidently been led into error by the 

 description and figures of Bruguiere, for the celebrated author of the ' History of Invertebrate 

 Animals,' though he had seen recent specimens, seems to have examined them very imper- 

 fectly, and to have taken for granted the correctness of the account in the 'Encyclopedic.' 

 He describes the polypes as " elongali cylindiici ; tentaculis circa orem 1 5 ad 20, erectis, 

 fasciculum turbinatum vel infundibuliformem uno latere imperfectum componentibus." To 

 Lamarck, however, notwithstanding the erroneous characters in this definition, is due the 

 credit of having been the first to distribute the fresh-water Polyzoa under three distinct and 

 peculiar genera, namely, Cristatella, Alcyonella, and Plumatella, a most important step 

 towards the further elucidation of the tribe. Lamarck associates Cristatella and Alcyonella 

 with Difflugia, a Rhizopod previously described by M. Leclerc, and with Spongilla, to con- 

 stitute, under the name of " Polypiers fiuviatiles" the first section of his " Polypes a Polypier " 



* Cuvier, 'Tableau elementaire de I'histoire naturelle des Animaux.' Paris, 1798. 



t Vaucher, Observations sur les Tubulaires d'eau douce. ' Bull. See. Philom.,' 1804, p. 157. 



J Bosc, ' Histoire Naturelle des Vers.' 



