134 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



sponges were related to the corals and hydroids, of course in a 

 very different sense from that in which Lamarck and his con- 

 temporaries united them with the Alcyonarians. Althoughthese 

 views have been disputed ever since, all men of science of the 

 present day nearly agree to the correctness of Leukart's statement. 

 Huxley (61) at that time considered the sponges to be colonies of 

 Protozoa, and called them " unicellular " organisms. In the sense 

 which Huxley applies to the word " unicellular " all animals would 

 have to be termed so, because all can be considered as colonies of 

 simple cells — Protozoa. 



in the same year Gray (62) described, among others, two 

 sponges, Carpenteria and Dujardinia, which, according to Gray, 

 hold an intermediate position between the sponges and the Poly- 

 thalamia. 



Lieberkiihn (63) classifies the sponges according to the anatomy 

 of their skeletons, and divides the whole of the sponges, in the 

 way Grant had insinuated, into four groups : Halisarcina, without 

 skeleton ; Spongina, with a skeleton, consisting of horny fibre ; 

 Calcispongina, possessing spicules composed of carbonate of lime, 

 and Halichondria possessiug spicules composed of silica. 



This classification has been adopted, more or less, by Bowerbank 

 and O. Schmidt, and has been taken by Zittel, whose classification 

 is now almost universally recognized, as the foundation of his own 

 system. 



In 1862, 0. Schmidt (64) published his well-known " Spongien 

 des Adriatischen Meeres," and described and figured very accurately 

 a great many species from the Adriatic ; since then for the last 22 

 years he has devoted all his time to the systematic description of 

 sponges, and the study of their genetic relationships. 



(61). T. Huxley. Zoological notes and observations. Annals and 

 Magazine of Natural History, 1851, Vol. VIII., p. 370; 1851, Vol. VIII. , 

 p. 433. 



(6 - 2). G. Gray. Desc iption of Aphroceros . Proc. Zool. Soc, Vol. XXVI., 

 p. 1 14. 



(63). N. Lieberkuhn. Neue Beitragczur Anatomie der Spongien. SI tiller's 

 Aivhiv., 1859, Beite, 353, 515. 



(GIJ. 0. Schmidt. Die Spongien des Adriatischen Meeres, Leipzig, 1862. 



