85 



ere ogsaa Musklerne paa de ufuldstændige ordnede. Længde- 

 musklerne ere stærkt udviklede og beklæde ikke alene 

 Septumets Hegge Sider, men ogsaa dettes fri Haml, hvor- 

 ved et Tversnit af et saadant Septum faar Udseende af 

 at være omgivet af en Glorie, Tab. XXIII, Fig. 8 k. 

 Disse ufuldstændige Septa ere golde, hvad der er ganske 

 ualmindeligt for Actinierne, imedens det synes at hore 

 hjemme hos Zoanthiderne. Saavel Septa som hele Gastro- 

 vascularhulheden er beklædt med et Endothel, der især paa 

 Kropsvæggen er meget bredt og bestaar af hoie, eilierende 

 Cylinderceller, Tab. XXIII, Fig. 7 <j. S /. med deres Kjerne 

 og Kjernelegeme. 



Svælgrøret er kort, cylindrisk og har paa dets indre 

 Plade line Længdefolder. samt to tydelig udprægede Svælg- 

 gruber, hvoraf den ene, sandsynligvis Bugfuren, er lidt 

 bredere end den anden. Til disse Svælggruber svare 

 de to Par Retningssepta saaledes, at hvert af disse 

 fæster sig udvendig paa Svælgrørets nederste Ende paa 

 et Punkt, der er netop modsat Randen af Svælggruben. 

 Tentaklerne, ligesom Mundskiven, bai - et Eetoderm, imellem 

 hvis Cylinderceller der er en stor Mængde Nematocyster, 

 som især paa Tentaklerne ere i stor Mængde tilstede. 



Findested. 



Station 164. Et Exemplar. 



Ogsaa med dette Dyr var jeg i stor Tvivl om, hvortil 

 jeg skulde henføre det. Liggende sammentrukket i Observa- 

 tionskarret lignede det i hoi Grad en Zoanthide, en Lighed, 

 der forsvandt noget ved dets fulde Udstrækning, men som 

 dog ikke ved den ndvendige Undersøgelse ganske kunde 

 opgives. Ved en nøiere anatomisk Granskning viste det 

 sig, at Cactosoma fjernede sig langt fra Zoanthidernes 

 Familie, imedens den nærmede sig stærkt til Phellidernes; 

 men heller ikke i denne Familie kunde den uden videre 

 Bemærkning indlemmes; thi foruden at det inkrnsterede 

 Overtræk ikke egentlig er en organiseret Cuticula, saa er 

 jo den Omstændighed, at det er ' de fuldstændige Septa, 

 der ere fertile, noget der er fremmed for Familien. Heller 

 ikke har den Acontier, hvilke jo skulde tilhøre Phelliderne. 

 Cactosoma er, saa forekommer det mig, en Overgangsform, 

 der stræber hen mod Zoanthiderne. Jeg har imidlertid 

 for det Første henført den til Familien Phellidæ, Andres, 

 senere kan den muligens komme til at danne en egen 

 Familie. 



Slægtskarakter. 



Legemet kolleformet med inkrusteret Overtræk; den 

 øverste Del nøgen. Udpræget Fodskive. Kroppens Over- 

 flade forsynet med Sugevorter. , 2 Rekker retraktile Ten- 

 takler. 6 Par fuldstændige Septa, hvoraf 2 Par Retnings- 



rounded (Pl. XXIII, tigs. 7, 8). In the same manner as 

 on the perfect septa, the muscles are also arranged on the 

 imperfect ones. The longitudinal muscles are strongly 

 developed, and clothe not only both sides of the septum 

 hut also its free margin, so that the section of such a 

 septum acquires the appearance of being surrounded by a 

 halo (Pl. XXIII, fig. 8 k). These imperfect septa are 

 sterile. :i feature quite uncommon in the Actidinæ, although 

 it appears to be a feature of the Zoanthidæ. Both septa 

 and the entire gastral eavitv are clad with an endothelium 

 which, espeeially on the wall of the body, is verv broad, 

 and consists of high eiliating cylinder-cells (Pl. XXIII, 

 figs. 7 g, X h with their nuclei and nucleus-corpuscles. 



The æsophagus is short and cylindrical, and upon 

 its inner surface has fine longitudinal folds, also two dis- 

 tinctly marked gullet-grooves, of which the one, probably 

 the ventral furrow, is a little broader than the other. The 

 two pairs of directive septa correspond to these gullet- 

 grooves in such manner, that each ot them attaches itself, 

 externally, to the lowest extremity of the æsophagus, 

 at a point which is exactly opposite the margin of the 

 gullet-groove. The tentaeles, as well as the oral disc, 

 have an eetoderm between wdiose cylinder-cells there is :i 

 large multitude of nematocysts which are, especially on 

 the tentaeles. present in great numbers. 



Habitat. 

 Station No. 164. One speeimen. 



Also in regard to this animal I was in great dubiety 

 as to how it should be assigned. Lying contracted in the 

 glass jar, it greatlv resembled a Zoanthid, a resemblance 

 that disappeared, somewhat, upon its complete extension, 

 but could, however, not be quite abandoned on the external 

 investigation. Upon a more perfect anatomical study it 

 appeared, that Cactosoma was far removed from the family 

 of Zoanthidæ, whilst it approached, considerably, to that 

 of the Phellidæ, but not even in that family could it be 

 included without further remark , because, besides the 

 feature that its encrusted covering is not really an organic 

 cuticulum, there is added, further, the circumstance, that 

 it is the perfect septa which are fertile, a feature foreign 

 to the family. Neither has it acontia, which is supposed 

 to be a feature of Phellidæ. Cactosoma is, it appears to 

 me, a transition-form striving towards the Zoanthidæ. I 

 have. in the nieantime, preliminarily assigned it to the family 

 Phellidæ, Andres; perhaps by and bye it may come to 

 form a family by itself. 



Generie characteristics. 



The body claviform, whith an encrusted covering, the 

 uppermost part bare. Distinguished pedal disc. The 

 surface of the body furnished with suckers. 2 series of 

 retractile tentaeles. ti pairs of perfect septa., of which 



