27 



og viste sig som mere eller mindre langt fremragende 

 kortstilkede Knopper. De stode, ligesom tidligere, ad- 

 spredte overalt paa Kroppen uden nogen synbar Orden. 

 Den ene Ende af Kroppen (a) bemærkedes at gaa ud i 

 en fremstaaende conisk Knude, som var mere end dob- 

 belt saa tyk som Tentaklernes Endeknop, og hvis afstud- 

 sede Ende syntes at have en cirkelrund Fordybning lige- 

 som en Sugeskive. Det er formodentlig med denne Ende 

 at Ungen senere hefter sig fast. Den anden modsatte 

 Ende (b) var tættere end den hele øvrige Krop besat med 

 Tentakler, hvilke ogsaa der vare stillede mere krandsfor- 

 migt om dens Midtpunkt, hvor der dog endnu ikke viste 

 sig noget Spor af Mundaabning, og vare mindre, ligesom 

 om de især herfra voxede frem. Det synes at disse Un- 

 ger, ved saaledes efterhaanden at voxe i Længderetningen 

 og fæste sig med den ene eller bageste Ende, snart op- 

 naa en fuldkommen Lighed med Moderdyret eller Am- 

 men, saa at her kun en ufuldkommen Generationsvexel 

 finder Sted. 



Man ser af den foregaaende Fremstilling, at Udvik- 

 lingen hos Myriothela paa en mærkværdig Maade afviger 

 fra samme hos alle andre hidtil bekj endte Arter af Cory- 

 neernes Familie, hvortil dette Dyr efter dets hele Bygning 

 dog nærmest slutter sig. Nogle Coryneer producere nem- 

 lig, som bekjendt, Kjønsdyr, der udvikle sig til virkelige 

 Meduser, som løsne sig fra deres Ammedyr og senere i 

 den frie Tilstand frembringe i sig Kjønsstoffer og derved 

 en infusorielignende, med Fimrehaar (Cilier) besat Yngel 

 (den saakaldte Planula), hvilken efter en kort sværmende 

 Tilstand sætter sig fast for at udvikle sig til Ammedyrets 

 Form igjen. Andre frembringe saakaldte Kjønskapsler 

 eller ufuldkomne medusoide Kjønsdyr, hvilke stedse for- 

 blive i continuerlig Sammenhæng med deres Ammedyr og 

 aldrig løsne sig fra det, men i denne Tilstand udvikle i 

 sig Kjønsstoffer og derved en lignende infusorieagtig Yn- 

 gel som hos hine, hvilken gjennemgaar den samme Ud- 

 viklingsmaade for efter en kort sværmende Tilstand igjen 

 at vende tilbage til Hydroideformen. 



Den unge Myriothela gjennemgaar intet saadant svær- 

 mende infusorieagtigt Udviklingsstadium; den erholder 

 allerede tidligt sine blivende Tentakler og udvikler sig 

 allerede indenfor Kjønskapselen til en formelig ung Hy- 

 droide. Myriothela forholder sig altsaa i denne Hen- 

 seende ganske som nogle Arter af Slægten Tubularia (me- 

 dens andre udvikle fuldkomne meduseagtige Kjønsdyr, der 

 forholde sig som de lignende hos mange Coryneer), nemlig 

 Tubularia larynx, og Slægten Hydra, hos hvilke Ungerne 

 ligeledes allerede i det Indre af Kjønskapslerne udvikle 

 sig til unge Hydroider, idet de overspringe den første 

 infusorieagtige Embryontilstand. 



Denne Slægt vil kunne diagnoseres saaledes: 



Genus Myriothela, Sars. 

 Animal solitarium, nudum, cylindraceum, appendicibus 

 cirriformibus liberis ab inferiore parte corporis exeuntibus 



width of the body; others were smaller, and appeared 

 like more or less prominent short-stalked buds. They 

 stood, as before, distributed everywhere on the body 

 without apparent order. One end of the body (a) was 

 observed to extend itself in a projecting conical tubercle, 

 which was more than twice as thick as the terminal knob 

 of the tentacles, and at the truncated extremity of which 

 there appeared to be a circular hollow like a sucker. 

 It is probably by this extremity that the young animal 

 fixes itself. The other opposite extremity (b) was more 

 thickly covered with tentacles than all the rest of the 

 body; and the tentacles were also placed more re- 

 gularly around its central point, where no trace of an oral 

 aperture was yet visible; and they were smaller at this 

 place, as if they grew out specially therefrom. It ap- 

 pears that these young ones, thus gradually growing in 

 the longitudinal direction, and attaching themselves by 

 the posterior extremity, soon acquire a complete resem- 

 blance with the parent or nursing animal; so that only 

 an imperfect alternation of generation takes place. 



It may be seen from the foregoing description, that 

 the development of the Myriothela differs in a remar- 

 kable manner from that of all the hitherto known spe- 

 cies of the Corynidæ family, with which this animal has, 

 according to its whole structure, the closest affinity. 

 Some Corynæ produce, as is well known, sexual animals, 

 which develop themselves into real medusæ, detach them- 

 selves from the parent animal, and afterwards in the free 

 state produce in themselves sexual matter, and thereby 

 generate young infusoria-like ciliated animals (the so- 

 called planulæ) which latter, after spending a short time 

 in a roving state, attach themselves in order to develop 

 themselves again into the form of the parent animal. 

 Others again produce the so-called sexual capsules, or 

 imperfect medusoid sexual animals, which remain always 

 in continuous connexion with the parent animal and never 

 detach themselves, but in this state develope in them- 

 selves sexual matter and thereby generate a similar infu- 

 sorial offspring, which goes through the same phases of 

 development, and after a short time spent in a roving 

 state, returns again to the hydroid-form. 



The young Myriothela goes through no such roving 

 infusorial phase of development; it receives at an early 

 period its permanent tentacles, and is developed already 

 within the sexual capsule to a regular young Hydroid. 

 The Myriothela is therefore in this respect quite like 

 some species of the genus Tubularia (while other species 

 develope perfect medusa-like sexual animals similar in life 

 and growth to those of many Corynidæ) for instance Tu- 

 bularia larynx and the genus Hydra, in which the offspring 

 are likewise developed into Hydroids while within the 

 sexual capsules, escaping the preparatory infusorial state. 



This genus may be thus diagnosticated. 

 Genus Myriothela, Sars. 



Animal solitarium, nudum, cylindraceum, appendici- 

 bus cirriformibus liberis ab inferiore parte corporis exe- 



4.* 



