106 



ere begge stærkt gulfarvede. Retractoren, der fæster sig 

 i Bunden af Zooeciet (Tab. 3, Fig. 14 d) danner under 

 Sammentrækningen en tydelig Spiral (Fig. 4 f). Paa hver 

 Side af Tentakelskeden findes en temmelig lang Retrac- 

 tionsmuskel, der gaar ned og fæster sig paa den indven- 

 dige Flade af Zooeciet, et godt Stykke ovenfor Bunden 

 (Parieto-vaginalmuskler). Foruden disse Muskler, er der 

 tillige et Par Parietalmuskler. Med Hensyn til Nervesy- 

 stemet, saa afviger det ikke væsentlig fra Smitts Beskri- 

 velse over samme hos Bugula, men hvad det saakaldte 

 Colonialnervesystem betræffer, saa have vi vistnok seet 

 de klare netformige Udbredninger, som af flere Forfattere 

 ere antagne for et fælles Nerveapparat for hele Dyrstok- 

 ken, uden at vi dog have kunnet overbevise os om, at 

 det virkelig er Nerver. Nogen Forbindelse mellem dette 

 Colonialnervesystem og det Nervesystem, der tilhører det 

 enkelte Dyr, have vi ligesaalidt som Nitsche kunnet 

 iagttage. 



Æggestokken er fæstet til Endocysten paa den øver- 

 ste og indvendige Del af Zooeciets Flade, og bestaar af 

 et Agglomerat af Celler, hvori Æggene udvikles. Vi have 

 havt Anledning til at iagttage næsten fuldt udviklede Æg, 

 3 — 4 liggende ved Siden af Æggestokken, hvori forøvrigt 

 saaes Æg i de tidligste Stadier. 



Nede i Bunden af Zooeciet findes Testikkelen, der dan- 

 nes af lignende Celler, som de der findes i Æggestokken; 

 kun vare de fyldte af Zoospermer, hvoraf mange vare 

 frigjorte og bevægede sig temmelig livligt. Kinetoskias 

 Smittii er altsaa i Lighed med en hel Del andre Bryozoer 

 en fuldstændig Hermaphrodit. 



Vi have ovenfor beskrevet et særegent Muskelapparat, 

 tilhørende ethvert enkelt Individ. Dette bestaar af en 

 meget stærk Muskel, som ved sin tykke Tendo fæster sig 

 paa det underliggende Zooecium, medens dens øvre vif- 

 teformige Del udbreder sig paa det overliggende Zooeci- 

 ums forreste Flade. Denne, der indtager Størstedelen af 

 Mundareaen, er tyndere, blødere og bøieligere, end den 

 bagerste Flade, og er derfor mere skikket til at rette sig 

 efter Muskelbevægelsen, ligesom den behøver mere Be- 

 skyttelse, baade fordi den er tyndere, og fordi Aabningen, 

 hvorigjennem Dyret udstrækker sig, staar nærmere denne 

 Side. Naar Muskelen sammentrækker sig, bevæges Zooe- 

 ciet nedad, og naar den slappes, indtager det igjen sin 

 opreiste Stilling. Men da den Aarsag, som fremkalder 

 Sammentrækning i en Muskel, som oftest virker samtidigt 

 paa mange, saa er Følgen den, at en stor Del af Grenen 

 eller endog den hele sættes i Bevægelse. Det er forre- 

 sten ganske interessant at iagttage, hvorledes Grenene 

 Stykke for Stykke bøies, alt eftersom flere og flere Muskler 

 sættes i Bevægelse, og naar denne er fuldstændig, ere 

 Grenene næsten sammenrullede, hvorved Polyzoariets 

 Skjærm antager en kugleformig Figur. Noget colonialt 

 Muskelsystem findes ikke. 



Saavidt os bekjendt er det blot Slægten Mimosella, 



are both strongly yellow-colored. The retractor, which 

 is attached at the bottom of the zooecium (Tab. 3 

 fig. 14 d), forms when contracted a distinct spiral (fig. 4 f). 

 On each side of the tentacular sheath, there is a rather 

 long retractor-muscle, which goes down and attaches 

 itself on the interior surface of the zooecium some distance 

 above the bottom (parieto-vaginal muscles). Besides these 

 muscles, there are also a pair of parietal muscles. With 

 respect to the nervous system, it does not differ essenti- 

 ally from Smitt's description of the same in Bugula; but 

 as regards the so-called colonial nervous system, we have 

 certainly seen the clear reticular enlargements, which by 

 many authors have been taken for a common nervous 

 apparatus for the whole animal complex, without our 

 having been able to convince ourselves that they are 

 really nerves. We have not been able, any more than 

 Nitsche, to discover any connexion between this colonial 

 nervous system and the nervous system which belongs to 

 the individual animal. 



The ovary is attached to the endocyst on the upper 

 and interior part of the surface of the zooecium, and 

 consists of an agglomeration of cells wherein the ova are 

 developed. We have had opportunity to observe nearly 

 completely developed ova 3—4 lying by the side of the 

 ovary, where moreover ova in the earliest stages were 

 also visible. 



Down at the bottom of the zooecium is found the 

 testicle, which is formed of similar cells to those which 

 are found in the ovary; only they were filled with sper- 

 matozoa, many of which were free, and moved about in 

 a rather lively manner. The Kinetoskias Smittii is there- 

 fore, like a great number of other Bryozoa, a complete 

 hermaphrodite. 



We have above described a peculiar muscular appa- 

 ratus belonging to each single individual. This consists 

 of a very strong muscle attached by its thick tendon to 

 the subjacent zooecium, while its upper fan-like part ex- 

 tends itself over the anterior surface of the superincum- 

 bent zooecium. The latter, which occupies the greater 

 part of the oral area, is thinner, softer and more flexible 

 than the posterior surface, and therefore better adapted 

 to conform itself to the muscular movement, as also it 

 requires more protection, both because it is thinner, and 

 because the aperture, through which the animal protrudes 

 itself, is nearer to this side. When the muscle contracts 

 itself, the zooecium is moved downwards, and when it is 

 relaxed, the zooecium resumes its erect position. But as the 

 cause which produces contraction in a muscle, most fre- 

 quently acts simultaneously on many, the consequence 

 is, that a great part of the branch, or even the whole of 

 it, is put in motion. It is moreover very interesting to 

 observe, how the branch bends bit by bit, accordingly as 

 more and more muscles are set in motion; and when 

 this is complete, all the branches are nearly rolled toge- 

 ther, whereby the umbrella of the polyzoarium assumes 

 a globular form. There is no colonial muscular system. 

 So far as we know, it is only the genus Mimosella, 



