ACTINIARIA 



177 



Textfig. 178. Epiactis 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 muscles 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 like 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 high 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: 



dm dm 



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, the mesenteries of the third cycle were the least expanded on the actinopharynx. The 

 longitudinal muscles form rather strong pennons with folds of about equal height. The parieto-basilar muscles 

 were very broad in the proximal part and almost reach the sphincter. Oral stomata and sometimes marginal 

 stomata were present, probably the latter are not permanent. The species is dioecious. All the stronger 

 mesenteries are fertile. The ova are very large and rich in yolk. Of 9 examined specimens 3 were males and 

 6 females, 3 of the latter were furnished with brood-rooms. 



Epiactis arctica (Verr.). 



PI. 3, Figs. 8 — 10. PI. 4, Fig. 9. 



Phellia arctica n. sp. Verrill 1868 p. 328. 1868 p. 490. Andres 1883 p. 342. 

 Pseudophellia arctica Verr. Verrill 1899 p. 376 textfig. 34. 



Diagnosis: Column elongated, covered with a well-developed but easily deciduous cuticle, and sprinkled 

 with spots of special structure. Fossa distinct. Sphincter of palmate or palmate-pinnate type. Tentacles con- 

 ical, not or slightly longitudinally furrowed, in numbers from 31 — 38 (6+6 + 12+ an imperfect 4th cycle). 

 Gonidial tubercles distinct. Actinopharynx long with at least 24 longitudinal ridges and two well-developed 



The Ingolf-Expedilion. V. 9. 



23 



