. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. ACTINIARIA 177. Textfig. 178. Epiaclis marsupialis. Transverse section of sphincter. specimen, the sphincter was proximally furnished with a main lamella which, however, soon became branched (textfig. 178, transverse section of the sphincter), in another specimen there was no main lamella in the sphinc- ter. The longitudinal muscles of the tentacles and the radial nmscles of the oral disc are ectodermal, but the folds are rather low and only take up a small part of the height of the ectode
. The Danish Ingolf-expedition. Marine animals -- Arctic regions; Scientific expeditions; Arctic regions. ACTINIARIA 177. Textfig. 178. Epiaclis marsupialis. Transverse section of sphincter. specimen, the sphincter was proximally furnished with a main lamella which, however, soon became branched (textfig. 178, transverse section of the sphincter), in another specimen there was no main lamella in the sphinc- ter. The longitudinal muscles of the tentacles and the radial nmscles of the oral disc are ectodermal, but the folds are rather low and only take up a small part of the height of the ectoderm. The folds are arranged Uke palisades, and at the insertions of the mesenteries on the oral disc con- siderably weaker and not as closely packed as in the middle parts. The ectoderm of the actinopharynx is very liigh in the ridges, in the furrows considerably lower. The mesenteries were in 5 examined specimens 48 (6 + 6 -|- 12 pairs). The pairs of the third cycle were un- equally developed. 6 pairs were strong, perfect and had well- developed reproductive organs and filaments, the other 6 pairs were weak, imperfect, in certain cases not reaching to the tentacular region, were devoid of reproductive organs and generally also of filaments. The six weaker pairs were in all specimens likewise arranged. If we use numbers to designate the different cycles of mesen- teries and begin with the one directive pair {dm), the weaker pairs (designated by spaced out figures) were grouped in the following manner: (I m d III 132313231323132313231323 In the largest specimen (with 47 tentacles) the weaker pairs of the third cycle were in the distal part furnished witli small filaments. Therefore it is possible that these mesenteries in still older specimens obtain longer filaments and perhaps also reproductive organs. All the stronger mesenteries were perfect. The me- senteries of the first cycle were coalesced with the actinopharynx to a larger extent than the mesenteries of the second order,
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Keywords: ., bookcentury1800, bookdecade1890, booksu, booksubjectarcticregions
