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mod Gastralhulhedens Buiul udspringe Generationsorganerne. 

 Kun Ims et Dyr lykkedes det at iagttage Æggestokke. der 

 vare vderst lidet udviklede. 



De cirkulære Muskler, som ere endodermale, ligge 

 paa Gastralhulhedens Væg i regelmæssige, baandformige 



Bundter, adskilte ved et meget smalt Mellemrum, hvori 

 sees dels runde, dels aflange Aabninger (Cinclides). I disse 

 sees paa et Par Steder Acontier at være indtrængte. 

 Om disse Aabninger perforere Huden eller kun trænge et 

 Stykke ind i Bindevævet, kan jeg ikke afgjore. Vel lindes 

 der lignende Aabninger paa Kroppens ydre Plade, men 

 hvorvidt disse korrespondere med de indre Aabninger, har 

 jeg ikke kunnet overbevise mig om; thi ved Tversnit er 

 det ikke lykkedes at paavise en saadan Kommunikation ; 

 sandsynligt er det imidlertid, da jeg har fundet Acontier 

 siddende saavel i indre som i ydre Aabninger. Svælgrørel 

 er cylindrisk, omtrent en Trediedel saa langt som hele 

 Dyrets Længde; det er foldet paa langs og forsynet med 

 2 Gonidiegruber, der udgaa fra Mundvigene og strrekke 

 sig lige ned til Svælgets nederste, fri Ende. 



Den ovenfor leverede Beskrivelse vil formentlig godt- 

 gjøre, at Andvakia, ikke uden at gjøre Vold paa Systemet, 

 vil kunne henføres til nogen af de hidtil opstillede Familier 

 og endnu mindre til nogen kjendt Slægt, imedens den vistnok 

 maa henføres til den store Tribus, Hexactiniæ, Hertwig. 

 Andvakia maa i Uere Henseender tiltrække sig Opmrerk- 

 somheden og ikke mindst derved, at den tyder hen paa 

 at være en Overgangsform. I sin indre Bygning har den 

 adskilligt tilfælles med Sagartiderne og Phelliderne, imedens 

 den i det Ydre afviger væsentlig. Men selv den indre 

 Bygning er ved sine faa og næsten rudimentære, listefor- 

 mige, ufuldstændige Septa og ved sine stærkt udprægede, 

 endodermale Cirkulærmuskler saa yderst forskjellig fra 

 Sagartidemes Familie, at den ikke kan indregistreres i 

 denne. 



Ligesaa meget som den i sit Ydre afveg fra Sagar- 

 tiderne, ligesaa meget synes den netop ved sit Ydre at 

 nærme sig Gruppen Edwardsia; dens Legeme kan jo med 

 Lethed inddeles i den af Gosse for Slægten Edwardsia 

 benyttede Tredeling, hvilken jeg ogsaa har gjort Brug af; 

 men det er dog kun ved en overfladisk Betragtning. at 

 Sammenligningen med Edwardsia kan holdes oppe. Hele 

 den indre Bygning er jo grundforskjellig. Edwardsierne 

 have nemlig 8 Septa, hvoraf 2 Par ere Retningssepta. 

 imedens de øvrige 4 Septa ere enkle og optræde ikke 

 parvis. Alle Septa ere forsynede med Generationsorganer ; 

 Tentaklerne ere simple og i Almindelighed flere i Antal, end 

 der er Septa. Men helt anderledes forholder det sig med 

 Andvakia, hvilket tydeligt nok fremgaar af Beskrivelsen, 

 og som det derfor her er unødigt at gjentare. 



entire body. acontia are seated at longer or skorter inter- 

 vals (Pl. XI. fig. 10 ti), and quite at the bottom of the 

 gastral eavity the reproduetive organs appear. Only in a 

 single animal was I fortunate enough to observe ovaries. 

 which were, however, extremely Little developed. 



The circular muscles, which are endodermal, lie upon 

 the wall of the gastral eavity in regular, ribbon-like fasci- 

 culi, separated by a very narrow interval in which partly 

 round, partly oblong appertures are seen (cinclides). In 

 these apertures acontia are observed, at a couple of 

 places, to have forced themselves in. Whether those 

 apertures perforate the integument or only penetrate 

 partially into the connective-tissue, I cannot determine. 

 It is true that similar apertures are found upon the 

 outer surface of the body, but how far these correspond 

 whith the internal apertures, I have been unable to satisfy 

 myself, as. upon transversal section, it has not been pos- 

 sible to demonstrate a correspondence iu communication ; 

 such is however probable, as I have found acontia seated in 

 both the inner and outer apertures. The æsophagus is 

 eylindrieal and about one third part of the length of the 

 entire animal; it is longitudinally folded and furnished 

 with 2 gonidial grooves that issue from the oral angles 

 and stretch themselves right down to the lowest, free 

 extremity of the gullet. . 



The description given above will, it is hoped, de- 

 monstrate. that Andvakia cannot, without doing violence to 

 the system, be relegated to any of the hitherto established 

 families, and still less to any known genus, whilst it must 

 certainly he relegated to the great tribe, Hexactiniæ. 

 Hertwig. Andvakia must, in several respects, altraet 

 attention. none the less from its indication of being a 

 transition-form. In its internal structure it has several 

 things in common with the Sagartidæ and Phellidæ, whilst 

 in its externals it differs materially. But even the inner 

 structure is, owing to its few and almost rudimentary. 

 fillet-formed. imperfect septa and its strongly distinguished 

 endodermal circular muscles, so extremely different from 

 the family of Sagartidæ that it cannot be registered as 

 one of its members. 



Just as much as it, in its externals. differs from 

 Sagartidæ, does it appear, and just in its externals too. 

 to approach the group Edwardsia, Its body. for instance. 

 can with ease be divided into the triple division made 

 use of by Gosse for the genus Edwardsia. and which I 

 have also availed myself of, but it is only upon a cursor] 

 examination that the comparison with Edwardsia can be 

 maintained. The entire inner structure is, indeed, rad- 

 ically different. The Edwardsia have, for instance. S septa. 

 of which 2 pairs are directive septa, whilst the other 4 septa 

 are single, and do not appear in pairs. All the septa are 

 furnished with reproduetive organs. The tentacles are 

 plain aud, in general, more numerous than the septa 

 But the case is perfectly different in Andvakia. which is 

 distinctly enough shown by the description. and is. there- 

 fore, needless to repeat here. 



12* 



