ACTINXARIA j^ 



teries under the glandular streaks. The longitudinal muscles of the column were distinct, though they do 

 not seem to form a continuous lamella. The spirocysts of the tentacles were rare and about 14 — 17 x 2,5 // 

 in size, those of the column and of the oral disc very uncommon — after much searching in the maceration- 

 preparations I found only one spirocyst in the column and one pair in the oral disc. Also the nematocysts 

 are not particularly numerous and, Uke the spirocysts, they are of inconsiderable size, in the column 11 — 14 

 X 2,5 fi, in the tentacles 10 X 2 — 2,5 // to 19 X 3,5 // and in the actinopharynx 12 X 2,5 /u to 19 X 3,5 

 — 4,5 fi. The spiral thread is often discernible in the greater nematocysts of the tentacles and of the actino- 

 pharynx. I have examined the stinging capsules as well in one of tiie type-specimens as in the Ingolf- 

 specimen. 



Family Halcuyiidae (Endocoelactiidae) . 



Diagnosis: Protactininae with pedal disc not well defined from the column. The ectoderm of the 

 column as well as that of the actinopharynx with spirocysts, (spirocysts sometimes absent: in the column 

 of Halcurias endocoelactis, teste Stephenson). Longitudinal muscles as a rule absent in the column (in 

 Halcurias pilatus present, teste Mc. Murrich). No sphincter. Tentacles arranged either in two alternating 

 cycles or in several such, very much displaced (18 + 10 + 16 + 8 + 16) and not arranged as in the typi- 

 cal Actiniaria. Longitudinal muscles of the tentacles ectodermal, radial nmsdes of the oral disc ectodermal 

 or with a little tendency to be mesogloeal (meso-ectodermal) . Actinopharynx strong with i — 2 siphono- 

 glyphes. Mesenteries from the second cycle developed in the endocoels • — each pair of mesenteries with the 

 longitudinal muscles facing away from each other — and arranged either cyclically, or, from the 20( — 28) 

 mesentery-stage, bilaterally in 8 or in a few more development-zones. In the latter case each bilateral pair 

 consists of a micro and a macro-mesenterium (or of two equally developed mesenteries?). I,ongitudinal 

 muscles of the mesenteries mostly weak, sometimes forming pennons. All stronger mesenteries with repro- 

 ductive organs. 



In this family I (1918) have included the genera Halcurias Mc. Murr. (= Endocoelactis Carlgr.), 

 Synhalcurias Carlgr., Synactinernus Carlgr., Isacfinernus Carlgr. and Actinernus Verr. (= Porponia R. 

 Hertw.). Compare this paper. To these genera Stephenson (1918b) adds a new genus, Carlgfenia which 

 evidentlj' is nuich related to Halcurias and possibly might be referred to tliis genus. Concerning the species 

 Halcurias endocoelactis, described by Stephenson (1918a), it is questionable if this species really is an 

 Halcurias. The in certain respects incomplete description of the species, given by Stephenson, founded 

 on his examination of a single specimen, seems to me to indicate that we have to do with a distinct genus. 

 The arrangement of the mesenteries is not the typical //a/c/^^-ifls-distribution, but seems to be more irregular 

 as in Synhalcurias. Probably the development of the later mesenteries resembles that in Actinernus and is 

 also bilateral. It is, however, not quite identical as it looks as if the new mesenteries develop more unilaterally, 

 in so much as the development-zones seem to be found on both sides of the 4 mesenteries of the second cycle. 

 Judging from the description by Stephenson it forms a transition between the Halcurias- and the Ac- 

 tinernus-ty-pes. Also the absence of the spirocysts in the column, if not overlooked bj- Stephenson, — 

 (S. has examined the column only on sections and not on maceration-preparations which give the only cer- 



