14S ACALEPIIS IN GENERAL. Part I. 



animals, and for a more correct appreciation of the affinities of the lower animals 

 generally, that he deserves a prominent place in a history of their classification. 

 (Compare vol. 1, pp. 179 and 209.) His special contribntions to the systematic 

 arrangement of the Acalephs relate chiefly to the Siphonophora', and are expressed 

 in the following diagram : — 



LEUCKART'S CLASSIFICATION OF THE SiniONOPIIOK^E, 18.54. 



1st Family. Calycopljoriihv. 



1st Sub-family. Dlphyidc? : Abyla, Diiiliyes, Gak'dlaria, — Praya. 



2cl Sulj-family. Ilippojmditdce : Hip|)0|ioJius. 

 2(1 Family. Pliysojilioridiv. 



1st Sub-family. Stephanoinida : Ai)olrmia, Agalma, For>kalia. 



2d Sub-fiiniily. Physophoiida proper : Pliysopliura. 

 3d Family. Ehiiiopliysida; : Ehizopbysa. 

 4th Family. Pliysalidaj: Physalia. 

 5th Famil}-. Velellida?: Velella, Porpita. 



In the additions to the German edition of Van der Iloeven's Handliook of 

 Zoology, Leuckart has divided the Ctenophora? into two orders, the Em-ijdonmta and 

 Stcwstomata, — an arrangement already hinted at Ijy Eschscholtz and Van der Hoeven. 



Since Eschscholtz, no naturalist has made more extensive and more valuable 

 contriljutions to the natural history and anatomy of the Acale^^hs in general, than 

 (.regenbaur, who has extended his researches to all the orders of the class, includ- 

 ing the study of their development, in his comprehensive investigations. His classi- 

 fications of the different gTOups of the cla.ss contain much also that is new and 

 important, though I think he is mistaken in the rank he assigns to some of 

 them. The different works in which lie has jHiblished his researches are enumerated 

 above (p. 27, note 13, and p. 87, note 1.) The chief im2)ortance of Gegenbaur's 

 contributions to the classification of the Acalephs consists in the discrimination of 

 several new fixmilies among the naked-eyed Medusa", and more especially in the 

 ultroduction of a new consideration by which to distinguish the Discophorai projjer 

 from the naked-eyed Medusa^. It has been seen above, that Eschscholtz admitted 

 two divisions among the Discojihora^, one of which he called Discophora; phanero- 

 carpa?, and the other Discophora) cryptocar]^*, founding this distinction upon the 

 presence or absence of special pouches for the reception of the sexual apparatus. 

 Forbes admitted also two divisions, calling one Steganoj^hthalmata, because the eye- 

 specks are enclosed in a scalloped fold of the margin of the disk, and the other 

 Gymnophthalmata, because the eyespecks are exposed along the margin, in close 

 connection with the tentacles and the circular tuljes. CrCgenbaur founded a similar 

 subdivision upon the jiresence or absence of an inverted rim along that same 

 marsyin. 



