BY DR. R. VON LENDENFELD. 127 



De Lamarck (26), who deserves our attention as a general 

 Biologist through his work " Philosophic Zoologique," in which he 

 expounded our present ideas of the variability of species, and of 

 the descent of one form of animal life from another ; also devoted 

 some of his energy to the sponges. In his " Systeme des Animanx 

 sans Vertebres," he describes and figures 54 species, but unfortu- 

 nately also he mixes the sponges up with the Alcyonarians. He 

 believes, namely, that all sponges possess polypes, and that it is 

 only in consequence of deficient observation, that they had not 

 been seen in all species, he goes so far as to call the sponges 

 "Polypiers." 



Lamouroux (27) already describes 168 species, and he, although 

 copying Lamarck in many respects, states that the sponges are 

 very, and fundamentally different from the Alcyonarians. His 

 work is the best of the time. 



Cuvier (28) treated the sponges very superficially, and without 

 taking any notice of the former works of Ellis, Solander, Lamarck, 

 and Lamouroux. 



Of greater importance is A. T. Schweigger's (29) essay on 

 sponges. He was the first to use the anatomical structure for 

 classificatory purposes, and to point out the difference between 

 calcareous and other sponges. The prevailing opinion of his time, 

 that sponges contain polypes, which had as yet not been discovered, 

 he treats ironically, although in consequence of the deficient 

 methods of his time he is of course not able to prove their non- 

 existence. He also observed the movements of the Oscula, which 

 changed their diameter whilst he observed them. 



T. E. Gray (30) considered the sponges as plants, and stated, 

 that all sponges possess spicules. His observations were made on 



(26). M. De Lamarck. Histoire des animaux sans vertibres. Paris. 1S16. 



(27). T. Lamouroux. Histoire des polypiers coralles Jiexibles. Casn, 1816. 



(28). G. Cuvier. Eegne animal. Vol. IV., 1817, 



(29). A.T. Schweigger. BeobachtungenavfNaturhirtorischenReisen. Berlin, 

 1S19, and Handbuch der Naturgeschichte skekttloser ungegliederter Thiere 

 Leipzig, 1820. 



(30). T. E. Gray. On the situation and rank of sponges in the scale of 

 Nature. Zoological Journal, I., 1824, p. 46. 



