7. Anthozoa (incl. Hydrocorallia]. A. Zoantharia. 17 



7. Anthozoa (incl. Hydrocorallia). 



As to the spermia s. below, Allg. Biologie, Retzius. 



A. Zoantharia. 



See Browne ( 3 ), Hallez( 5 ), Plymouth, Stephens and Vaughan( 2 ). For 

 fossil forms see Bucking, Dainelli(V) 5 De Angelisl 1 - 3 ), Dennant( 2 ), Diener, 

 Drevermanni 1 , 2 ), Felixt 1 , 2 ), Jakowlew, Missuna, Shearsby, VaughanO), Wiman. 



Carlgren(') records Condylactis cruentata and describes the free-swimming 

 young which were taken at a depth of 200-450 m. They are all in the Ed- 

 wardsia-stsigQ, about 1 mm long, and bear no trace of tentacles. The mouth 

 is excentric and in two of the specimens examined there is an indication of 

 a siphonoglyph. The aboral end is often somewhat pointed, its ectoderm is 

 much thickened and bears very numerous closely arranged large nematocysts 

 with indistinct filament; besides these there are in greater number thin-walled 

 elongate nematocysts with clearly seen spiral thread. At the base of the aboral 

 ectoderm there is a well developed nervous layer with ganglion cells forming 

 a larval sense organ (this is the anterior end in swimming). In the thinner 

 ectoderm of the middle region of the body nematocysts are less numerous and 

 the nerve layer is seen with difficulty. In the oral region and stomodum 

 nematocysts are more numerous and a thin nerve layer is present. The single- 

 layered endoderm is thick and very vacuolated, so that it gives the impres- 

 sion of being in several layers. In the youngest stage the coslenteric pouches 

 are insignificant crescentic slits; the mesenteries develop first and the pouches 

 later (agrees with Appellof 1900, and differs from Gotte 1897). All the 8 

 mesenteries are complete and their muscle-ridges have the usual arrangement. 

 The ventro-lateral mesenteries are the first to be formed, they are the largest 

 and bear well developed filaments, while in the other mesenteries the filaments 

 are feebly marked and extend only a short distance below the stomodseum. 

 Only the glandular streak is present and this is obviously formed from the 

 stomodseal ectoderm. These larvae remind one of those 'of Lebnvnia (Duerden, 

 see Bericht f. 1899 Coel. p 12) except that a large mouth is present in G. 

 and the differentiation of the aboral end has proceeded further than in L.-larvse. 



Carlgren( 2 ) concludes that Polyparium ambulans is a torn-off piece of the 

 most distal part of an Actinian of the family Stoichactidae , the wound having 

 healed by fusion of the body wall with the oral disc. He found a similar 

 specimen (except that the body wall had not yet fused with the oral disc) in 

 the Stockholm Reichsmuseum ; and in an experimentally cut-off portion of the 

 distal body wall (with tentacles) and oral disc of Sagartia kept under good 

 conditions, fusion of the cut edges of the body wall and oral disc occurred, 

 the specimen lived a month but finally died from starvation. 



Carlgren( 3 ) describes the mesenterial musculature of Tealia davisii as typical 

 of that of the higher Actiniae. Each strong mesentery bears on one side 

 transverse muscles, a parieto-basilar and a basilar muscle, on the other side 

 longitudinal muscles and a basilar muscle. These muscles undergo modification 

 in correlation with the habit, c. g. in such forms as Chondraetinia which live 

 on a shell and move only to a very limited extent, the parieto-basilar and 

 basilar muscles are proportionately weak, as also are the basilar muscles in 

 elongate forms with a small pedal disc. In the Protanthese and the Athenaria 

 no basilar muscle is formed, in the Pr. this is associated with the absence of 



