The sponges were by Cuvier, and also by Lamarck, accorded a position among the Polypes, near Alcyonium, which represents the latter's _Polypiers empâtés_; and it is interesting to notice that, for many years remaining among the Protozoa, meanwhile even by Agassiz regarded as vegetables, they were by Haeckel restored to a position among the Coelenterates, though for over twenty years they have by some American zoölogists been more correctly regarded as a separate phylum.[124] Lamarck also separated the seals and morses from the cetacea. Adopting his idea, Cuvier referred the seals to an order of carnivora. Another interesting matter, to which Professor Lacaze-Duthiers has called attention in his interesting letter on p. 77, is the position assigned _Lucernaria_ among his _Radiaires molasses_ near what are now Ctenophora and Medusæ, though one would have supposed he would, from its superficial resemblance to polyps, have placed it among the polyps. To Lamarck we are also indebted for the establishment in 1818 of the molluscan group of Heteropoda. Lamarck's acuteness is also shown in the fact that, whereas Cuvier placed them among the acephalous molluscs, he did not regard the ascidians as molluscs at all, but places them in a class by themselves under the name of _Tunicata_, following the Sipunculus worms. Yet he allowed them to remain near the Holothurians (then including Sipunculus) in his group of _Radiaires echinodermes_, between the latter and the Vers. He differs from Cuvier in regarding the tunic as the homologue of the shell of Lamellibranches, remarking that it differs in being muscular and contractile. Lamarck's fame as a zoölogist rests chiefly on this great work. It elicited the highest praise from his contemporaries. Besides containing the innovations made in the classification of the animal kingdom, which he had published in previous works, it was a summary of all which was then known of the invertebrate classes, thus forming a most convenient hand-book, since it mentioned all the known genera and all the known species except those of the insects, of which only the types are mentioned. It passed through two editions, and still is not without value to the working systematist.