ACTINIAKIA 



The examined species from Sunde was a male with well developed spermatozoa. Only the 6 first 

 mesenteries are fertile. The information, given by Danielssen, that the reproductive organs appear in the 

 imperfect mesenteries, needs confirming. 



Family Ptychodactiidae. 



Diagnosis: Protactininae with pedal disc not well denned from the column. Longitudinal muscle- 

 aud nerve-layer in the column weak. Spirocysts in the ectoderm of the column few (or absent?). Sphincter 

 absent or very weak, endoclermal. Actinopharynx now very rudimentary, now well-developed, yet always 

 of large diameter and furnished with special arrangements accelerating the circulation. Mesenteries few 

 or numerous, all with reproductive organs. Muscles of the mesenteries weak, typically arranged. Ciliated 

 lobes of the filament absent. Incomplete mesenteries in the distal part above the glandular streak of the 

 filaments with curious structures giving the appearance of a half-funnel. Reproductive organs only in the 

 proximal parts of the mesenteries, the glandular streaks of the filaments more distal. 



Genus Ptychodactis Appellof. 



Diagnosis: Ptychodactiidae with low but broad column lacking all sorts of papillae. Spirocysts 

 in the ectoderm of the column very rare (or absent?). No sphincter. Tentacles numerous. Actinopharynx 

 short, possibly rudimentary, not distinctly differentiated from the oral disc, with curled aboral prolong- 

 ations on the stronger mesenteries. No siphonoglyphes. Mesenteries numerous, those of the first cycle, and 

 as a rule also those of the second, perfect. Glandular streaks of the filaments very meandrian. The proximal 

 parts of the mesenteries only slightly coalesced. 



Ptychodactis patula Appellof. 



PI. .). Fig. 6. 



Ptychodactis patula n. sp. Appellof 1893 PI. r 3. 

 App. Carlgren 1914 p. 13. 



Diagnosis: Body low, often disc-like, broader in the proximal end than in the distal one. Column 

 and pedal disc in preserved state with circular ridges and furrows. Tentacles in 4 5 (to 6?) cycles, about 

 100 122, a little smaller in number than the mesenteries, distinctly longitudinally sulcated conical, 

 short, with weak, ectodermal, longitudinal muscles. Oral disc with shallow, radial furrows and weak, radial 

 muscles, actinopharynx with ectodermal, longitudinal muscles. Curled prolongations of the actinopharynx 

 on the mesenteries of the first and of most of the second cycle. Pairs of mesenteries to about 72 (6 + 6 + 12 

 + 24 + one more or less complete fifth cycle). Parieto-basilar muscles and stomata absent. Spirocysts in 

 the column and in the oral disc extremely rare, also in the tentacles not common. Nematocysts not especi- 

 ally numerous and small, in the column about n 14 X 2 2,5 ;t, in the tentacles from 10 X 2 2,5 (i to 

 J 9 X 3.5 !> an d in the actinopharynx 12 X 2,5 /j. to 19 x 3,5 ;t. 



