i de mest forskjellige Former, fra 2-armede indtil 7-armede, 
fremgaar, at Delingen foregaar temmelig langsomt. Alt 
eftersom Spalten bliver dybere og videre, reproducerer Ski- 
veranden smaa, aflange Kalkstykker, hvorved den saagodt- 
Paa Hudskelettet sees dette tydeligst, 
idet de nyproducerede Kalkplader ere baade mindre end 
de gamle, staa længere fra hverandre, og bære kun en Pig, 
som ganske lukkes. 
imedens de gamle paa den øvrige Del af Skiven bære mange 
Pigge. Afsnoringen foregaar paa Bugfladen, først efterat 
den nysomtalte Proces er tilendebragt paa Rygsiden, og da 
paa den Vis, at de to første Par Adambulacralplader og 
Ambulacralpladerne med de to inderste Fodder blive til- 
bage. Fra det andet Par Adambulacral- og Ambulacralplader, 
samt fra den omgivende Hud, udspringer en liden, knap 
en halv Millimeter lang, konisk, blød Knop, 1 hvis Hud 
findes spredte Kalkkorn; men endnu ingen Skeletdannelse. 
Paa et Exemplar, der havde kastet 2 Arme, saaes to 
saadanne Knopper, der vare omtrent 1”” lange, og her 
iagttoges et tydeligt Anlæg saavel til Hudskelet som egent- 
lig Skelet, saaledes kunde ved nogen Forstørrelse sees baade 
Adambulacral- og Ambulacralpladerne, ligesom den ydre 
Hudflade var besat med enkeltstaaende Pigge. Imellem 
disse to smaa Arme saaes Begyndelsen til en 3die Arm. 
I en fraskilt Arm fandtes to Blindtarme, der ved 
korte Bindeveeystraade vare bundne til Ryghudens indre 
Væg, samt endel af Generationsorganet. 
Hvorvidt de fra Moderlegemet fraskilte Arme indivi- 
dualisere sig, hvorvidt Reproduktionsevnen hos dem er istand 
«til at danne Skive og Armer, med deri indesluttede Orga- 
ner, kunne vi ikke med fuld Sikkerhed afgjøre; men Sand- 
synligheden for en saadan Reproduktionsevne forekommer 
os at være stor, idet Dele af Mavens Udkrænkninger, der 
danne Blindtarme, fulgte med den fraskilte Arm, og vare 
paa det Exemplar, hvori vi iagttog Begyndelsen til Fra- 
skillelsen, bundne ved nydannede Bindevævstraade til Hu- 
dens indre Veg. Med Hensyn hertil har E. Haeckel først 
med Bestemthed udtalt sig for den Mening, at en saadan 
Reproduktion virkelig finder Sted, hvilken Mening han støt- 
ter paa lagttagelser anstillede paa Slegten Ophidiaster, og 
som ere offentliggjorte i en særdeles interessant Afhand- 
ling!. Her er dog at bemærke, at hos Ophidiaster fra- 
skilles ikke den hele Arm, saaledes som Tilfældet er hos 
Stichaster albulus, men en Stump af nogle Muillimeters 
Længde bliver tilbage og rager udenfor Skiven, og fra 
denne Stump sker Reproduktionen. Kan altsaa en saale- 
Die Kometenform der Seesterne und der Gene- 
Zeitsch. f. Wiss, Zoolog. 30ter 
r EK. Haeckel. 
rationswechsel der Echinodermen. 
Band, Supplement, pag. 424. 
the most varied forms, ranging, from 2-rayed, up to 7-rayed 
specimens; it appears that the division proceeds rather 
slowly. According as the fissure becomes deeper and wider, 
the diskal margin reproduces small, oblong, calcareous 
ossicles, by which the fissure becomes almost closed. This 
is most distinctly seen in the dermal skeleton, because, the 
newly produced calcareous ossicles, are, both, placed fur- 
ther apart, and are smaller, than the old ones, and they carry 
only one spine, whilst, the old ossicles of'the remainder of 
the disk carry numerous spmes. The constrictive separa- 
tion proceeds first on the ventral surface, after the process 
just spoken of is concluded on the dorsal surface, and 
then, in such a manner, that the first pair of adambulacral 
and ambulacral plates, with the two inmost suckers, are 
left behind. From the exterior pair of these adambulac- 
ral and ambulacral plates, as well also, as from the sur- 
rounding integument, there springs, a small, barely half a 
millimetre long, coniform soft knob, in whose integument 
scattered calcareous grains are visible, but not as yet any 
skeleton formation. 
In one specimen which had east two rays, two such 
knobs were visible, measuring about 1 millimetre long, and, 
there was, here, visible, a distinct tendency to formation of 
both, a dermal skeleton, as well as, a skeleton proper. 
With the assistance of a magnifyer, both adambulacral 
plates could thus be seen, whilst also, the exterior fintegu- 
mental surface was seen to be beset with spines, placed 
singly. Between these two small rays, the commencement 
of a third was perceptible. 
In a separated ray, 2 ceca were found, which were 
united to the inner wall of the dorsal integument, by short 
filaments of connective-tissue, and, also, by a portion of the 
generative organ. 
In what degree the rays separated from the parent 
body become individualized, or, in what degree the repro- 
ductive energy in them is able to produce disks, and arms, 
with their included organs, we. have not been able to de- 
cide with complete certainty, but, the probability of such a 
reproductive capacity, appears to us to be great, because, 
portions of the protrusions of the stomach forming the 
cæca, accompany the separated ray, and, in the specimen 
in which we observed the commencement of the separative 
process, these were connected to the wall of the integu- 
ment, by filaments of freshly formed connective tissue. But 
with regard to this E. Haeckel has first distinctly expressed 
himself of the opinion, that such a reproduction really 
takes place, and he bases his opinion, on his observations 
of the genus Ophidiaster, and which he has published in 
an extremely interesting memoir!. There is however to be 
remarked, here, that in Ophidiaster, the whole ray is not 
separated as is the case in Stichaster albulus, but a stump, 
of a few millimetres in length, is left, projecting from the 
t EF. Haeckel. Die Kometenform der Seesterne und der gene- 
rationswechsel der Echinodermen. Zeitsch. f. Wiss. Zoolog. 30ter 
Band. Supplement pag. 424. 
