Chap. II. CLASSIFICATIONS OF ACALEPHS. 145 



The classification of Lamarck, and the names he gave to the primary siib- 

 divisions of the Acalephs, trnly express the condition of onr science at that period. 

 The natural limits of the class had not yet been found, — nay, the Acalephs Avere 

 not yet separated from the Echinoderms, as a class, but Meduste had been observed, 

 a considerable number of them were superficially known, and, next to them, many 

 animals had been noticed, bearing evidently some relation or other to the Medusee ; 

 but what these relations were, was not imderstood ; and so all these species were 

 united into one group by the side of the regular Medusa?, under the name of 

 Anomalous Eadiates. 



Peron and LeSueur next investigated these groups singly, — LeSueur devoting 

 his attention chiefly to the compound ones, which he at this early period already 

 separated from the compound Tunicata, while, together with Peron, he illustrated 

 the Discophora3 generally. 



Cuvier's merits consist mainly in the separation of the Acalephs as a class ; but 

 the limits he assigned to it were not altogether true to nature. Schweigger only 

 copied Lamarck and Cuvier as fiir as classification is concerned. 



To Goldfuss, science is indebted for the first discriminating subdivision of the 

 Acalephs. For the first time the Cteuophora? were brought together by him and 

 separated from the Siijhonophorae, and these again divided into two families, Avhile 

 all DiscophonB remained together. Charaisso and Eysenhardt copied Goldfuss, Avliile, 

 still later, Latreille fell back upon the first outlines of Lamarck. 



Eschscholtz, next to Cuvier, ma}^ be considered as the founder of the classi- 

 fication of Acalephs, for while Cuvier distinguished the class, Eschscholtz first divided 

 it into three natural orders, one of Avhich he very properly sid^divided into two 

 divisions, already pointing in the direction of future progress; for hereafter the 

 DiscophoraB cryptocari^fB will appear more clearly allied to the Siphonophorse than 

 they are to the Discophor^ phanerocarpa?. His subdivision of the ordex-s into 

 natural families was a still greater improvement. DeBlainville did not mark a 

 progress in the study of this class : his suggestions were mere guesses, mostly far 

 out of the right course. Oken simj)ly copied Esclischoltz. Brandt added a few 

 families among the Siphonophorse, the number of which was still further increased, 

 often without much discrimination or criticism, by Lesson. Forbes, and Liitken also, 

 descriljed some new families ; but Forbes made an important addition to the classi- 

 fication of Eschscholtz, b}^ pointing out further differences between the two divisions 

 of the Discophora\ which he called Steganophthalmata and Gymnophthalmata. 



With Sars and Steenstrup a new epoch begins for the history of the Acalephs, 

 though neither of them has attempted to classify these animals; but it is to their 

 investigations that science is indel)ted for the first facts bearing upon the affini- 

 ties of the Hydroids to the Discophorte cryptocarpa?, or the Gymnophthalmata of 



VOL. ni. 19 



