ACTINIARIA 



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 p 

 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, like the spirocysts, they are of inconsiderable size, in the column n 14 

 X 2,5 (jt, in the tentacles 10 X 2 2,5 ft to 19 X 3,5 fjt and in the actinopharynx 12 X 2,5 ^ to 19 X 3,5 

 4,5 p. 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 the type-specimens as in the Ingolf- 

 specimen. 



Family Halcuriidae (Endocoelactiidae). 



Diagnosis: Protactininae with pedal disc not well denned 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 Me. 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 muscles 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 2o( 28) 

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

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

 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 Me. Murr. (= Endocoelactis Carlgr.), 

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

 Hertw.). Compare this paper. To these genera Stephenson (igiSb) adds a new genus, Carlgrenia which 

 evidently is much related to Halcurias and possibly might be referred to this genus. Concerning the species 

 Halcurias endocoelactis, described by Stephenson (igiSa), 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/cn'fls-distribution, but seems to be more irregular 

 as in Synhakurias. 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 Hakurias- and the Ac- 

 tinernus-types. Also the absence of the spirocysts in the column, if not overlooked by Stephenson, - 

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



