438 Dr. E. Haeckel on a new Form of 



latter [Carmarina, Geryonia) are distinguished by having all 

 their organs sextuple, and by their considerable size. With regard 

 to the conditions of reproduction in these animals, scarcely any- 

 thing has hitherto been known. According to a short notice 

 published by Krohn* in 1861, this most meritorious naturalist 

 Tiad, as early as 1843, observed a sexually mature female speci- 

 men of Geryonia proboscidalis, of which " the extremity of the 

 peduncle, reaching down freely into the stomachal cavity, ap- 

 peared thickly beset with buds in various stages of development. 

 In the less developed buds only the umbrella and peduncle 

 could be distinguished ; the further advanced ones had developed 

 not only the six tentacles, but also the marginal corpuscles." 

 This isolated observation, which seems to have attracted but 

 little notice, might have led, had it been followed out, to the 

 discovery of the wonderful phenomenon which will be described 

 immediately. 



Besides this we have hitherto had only the admirable descrip- 

 tion of a singular metamorphosis observed by Fritz Miiller, in 

 1859, in the larva of a quadruplex Geryonide of the Brazilian 

 coast f. The origin of this larva, which was captured swimming 

 freely in the sea, and which gradually became converted into 

 the sexually mature Liriope Catharinensis, remained unknown. 

 Hence it has been generally believed, although supported by no 

 direct observation, that the Geryonidce, like the Trachynemidce 

 and JEginidce, are propagated homogonically, and without any 

 alternation of generations. 



The Geryonidce which I had the opportunity of continuously 

 observing at Nice belong to two very different species. The 

 smaller species, Liriope (Glossocodon) eurybia, which occurs 

 there in abundance, is quadruplex, and has an umbrella of 

 8-10 millim. in diameter. This species undergoes a meta- 

 morphosis very similar to that of Liriope Catharinensis described 

 by Fritz Miiller. The second, much larger and rarer species, 

 which I have named Geryonia [Cai'marina] hastata, is sextuplex, 

 and attains a diameter of 50-60 millim. 



In the sextuplex Geryonidce a metamorphosis has not hitherto 

 been observed. I have, however, been able to trace this in its 

 whole course in numerous larvae of Geryonia hastata captured in 

 the open sea. The metamorphosis of the sextuplex Carmarinides 

 takes place on the whole in accordance with the same laws as 

 that of the quadruplex Liriopides, of course with the difference 

 that all the organs make their appearance to the number of six 

 or a multiple of six, instead of four or a multiple of four. The 



* Wiegmann's Archiv, xxvii. 1. p. 169, note. See Annals, ser. 3. vol. ix. 

 p. 8 (1862). 

 f Ibid. xxv. 1. p. 310. 



