125 



tager nitid Coenenchymet, som binder dem sammen, baade 



i Tykkelse og Bredde, Tab. XXI, Fig. 11. 12, 14, 15. men 

 forbliver temmelig glat uden Tendens til at neste sig. og 

 synes at være saa fast. at det holder Kolonien godt samlet. 

 Kun paa yderst faa Exemplarer har jeg iagttaget, at Knop- 

 skydningen foregaar fra Basaldelens nederste Sidedel, Tab. 

 XXI, Fig. 1. 5. 10; i Regelen foregaar den fra Coenen- 

 chymet. Stundom kan Coenenchymet, der sammenbinder 

 tiere Polyper, være temmelig smalt, men det er dog altid 

 afrundet, fast og meget stærkt inkrusteret; Inkrustationen 

 er bestandig stærkere end paa selve Polyperne. Disse 

 større eller mindre Kolonier af Polyper holde godt sammen; 

 de ligge lost i Sandet, og de enkelte Individer i Kolonien 

 viser ingen Tendens til at skille sig fra sine Kamerater. 



Dr. Erdmann mener at hos hans Slægt løsriver de 

 enkelte Individer sig for at danne en ny Koloni, efterat 

 de ere frigjorte. Han ytrer: ..Die Abschniirung scheint 

 bestandig fortzuschreiten und schliesslich zur ganzlichen 

 [solation des Tochterthieres zu fiihren". Saaledes er i 

 alle Fald ikke Forholdet hos Slægten Mardøll. Af de 

 mange Hundrede Exemplarer, jeg har undersogt, tindes 

 der ikke noget, som tyder hen paa en saadan Isolation. 

 Sagtens lindes der nogle isolerte Polyper, der i deres Basal- 

 ende har en fin Aabning, som efter Erdmann skulde tyde 

 hen paa en Afløsning fra Moderdyret; men denne Aabning 

 tyder aabenbart hen paa, at Dyret ved ydre Vold er fra- 

 røvet Kolonien. Derimod lindes flere isolerede Polyper, 

 hos hvem alt peger i den Retning, at de ere udviklede af 

 Æg, og som blive Stampolyper for den vordende Koloni. 

 Disse Stampolyper ere langstrakte, kolleformede og fuld- 

 kommen afrundetle i deres Basalende, der er jævn og uden 

 Spor af Aabning eller andet, som kunde fure Tanken hen 

 paa en Aflosning, Tab. XXI. Fig. 19, 20. Fra en saadan 

 Moderpolyps Grunddel er det da. den første Knop skyder 

 ud. Tab. XXI, Fig. 6, og fra nu af er Kolonisationen sat 

 i Gang. 



For Mardølls Vedkommende kan der saaledes ikke 

 godt blive Tale om Enkeltpolyper, „Einzelpolypen", som et 

 Karakteristikon for Slægten; thi aabenbart lever den i 

 Kolonier ligesaa fuldt som Slægterne Polythoa og Epizoau- 

 thus; men hvad der er karakteristisk, er unægtelig den 

 Særegenhed, at imedens de sidstes Kolonier ere fæstede 

 ved et mere eller mindre udbredt Coenenchym til forskjel- 

 lige Gjenstaude. ere Mardollkohmierne ikke fæstede, men 

 leve ved deres afrundede, tildels halvkugleformede , egale 

 Coenenchym, frit i eller paa Sandet. Efter dette har jeg 

 ikke kunnet henføre Slægten Mardøll til Familien Spheno- 

 pidæ, Hertwig, da den hverken er en enkeltlevende Zoan- 

 anthide eller har nogen Hefteskive, der fæster den til 

 Bunden, men har maattet danne en ny Familie for den. 



two polyps there spring several (Pl. XXI. fig. ;;. 4. 9). 

 As the growth of the young polyps proceeds, sn does 

 the sarcosoma which unites them together also increase, 

 both in thickness and breadth (Pl. XXI, fig. 11, 12. 14, 

 15), but remains pretty smooth, without auy tendency to 

 attach itself, and appears to be so firm, that it retains the 

 colony well together. Only in extremely few specimens 

 lune I observed the budding proceed from the lowest 

 lateral part of the basal portion (Pl. XXI. fig. 1, 5, 10). 

 It usually proceeds from the sarcosoma. Occasionally the 

 sarcosoma that unites several polyps together may be 

 rather narrow. but it is. however, always rounded, firm, 

 and very strongly encrusted. The encrustation is always 

 stronger than on the polyps themselves. These larger or 

 smaller colonies of polyps hold well together; they lie 

 loose in the sand, and the individuals of the colony show 

 no tendency to separate themselves from their neighbours. 

 Dr. Erdmann thinks. that in his genus the individual 

 members detach themselves in order to form a new 

 colony after the detachment has tåken place. He says : 

 ..Die Abschnurung scheint bestandig fortzuschreiten und 

 schliessclich zur ganzlichen Isolation des Tochterthieres zu 

 fiihren-. Such is, at any rate, not the case in the genus 

 Mardoll. In the many hundreds of specimens I have 

 examined there is nothing to be observed that indicates 

 any such an isolation. True enough, there are found a 

 few isolated polyps that in their basal extremity have a 

 minute aperture, which, according to Erdmann. would 

 indicate a separation from the parent animal; but this 

 aperture evidently points to the animal having become 

 detached from the colony owing to extemal violence. On 

 the other hand, several isolated polyps are found, regarding 

 which everything points in the direction that they have 

 been developed from ova, and which become the parent 

 polyps of the prospective colony. Those parent polyps 

 are elongate, claviform, and perfectly rounded in their 

 basal extremity, which is even and without trace of aper- 

 ture or any feature that could lead to the thought of a 

 detachment having occurred (Pl. XXI, fig. 19, 20). It is 

 from such a parent polyp's base that the first bud there- 

 fore shoots forth (Pl. XXI, fig. 6), and from that time the 

 colonisation progresses. 



There can, therefore, in regard to Mardoll, scarcely 

 be any talk of single polyps, „Einzelpolypen", as a charac- 

 teristic feature of the genus; because they evidently exist 

 in colonies just as well as the genera Polythoa and Epi- 

 zoauthus; but what is a characteristie feature, is. indisput- 

 ably, the peculiarity, that while the colonies oi' the last- 

 named are attached by a more or less broad sarcosoma 

 to various objects, the Mardoll colonies are not attached, 

 but exist with their round, sometimes semispherical, even 

 sarcosoma free, in or upon the sand. For these reasons 

 I have not been able to assign the genus Mardoll to the 

 family Sphenopidæ, Hertwig. as it is neither an isolated 

 Zoanthid nor lias it any attachment-disc that secures it 

 to the sea-bottom, and I have therefore been obliged to 

 form a. new family for it. 



