ACTINIARIA 



Genus Protanthea Carlgr. 



Diagnosis: Gonactiniidae with smooth column which is broader in the distal part than in the 

 proximal one. Longitudinal muscle layer and nerve-stratum very well developed. Tentacles long, numerous, 

 at the base a little constricted, in the apex not swollen. Oral disc conical. Only the 8 "Edwardsia-mesen- 

 teries" perfect. All stronger mesenteries with filaments and reproductive organs. No differentiation into 

 filament-mesenteries and genital-filament-mesenteries. Sterile, weak mesenteries in variable numbers in 

 the distal part of the body. 



Protanthea simplex Carlgr. 



Protanthea simplex sp. n. Carlgren 1891 a p. 81, textfigs. 



Carlgr., Carlgren 1893 p. 24. PI. i figs. 9, 16, PI. 3. figs, i 7, PI. 4. figs. 3 10. PI. 

 10. fig. 2. 1905 p. 158, Arndt 1912, p. 123, Grieg 1913, p. 143. 



Diagnosis: Body cup-like with 24 rather distinct, longitudinal furrows, without fossa. Margin 

 undulated. Tentacles numerous from about 100 to 160 in 5 or 6 cycles, the inner ones about the length of 

 the column or longer, the outer ones considerably shorter. Actinopharynx with numerous, weak, longitudi- 

 nal furrows and 6 deeper of which 2 form the siphonoglyphes which are aborally prolongated. Pairs of fila- 

 ment- and genital- mesenteries 6 + 6 = 12 in the whole length of the body. Numerous sterile, filament- 

 lacking mesenteries in the distal part of the body, in number corresponding to that of the tentacles. Lon- 

 gitudinal muscles of the mesenteries weak, with low folds, form no pennons. Parieto-basilar muscles weak, 

 not folded. No stomata. Nematocysts in the ectoderm of the column rib-like, partly 17 22 X 1,5 to 2 /t, 

 partly 29 50 x 3 3,5 {i, in the tentacles partly 19 24 X 2 2,5 //, partly 4458 x 3,5 4 fi, the latter 

 very numerous and closely arranged in the distal part (batteries of stinging cells), in the actinopharynx 

 22 31 X 2 2,5 ft. Spirocysts in the ectoderm of the column and tentacles from about 22 X 2,5 // to 43 

 X 5 (i, very numerous in the column and in the proximal part of the tentacles, in the distal part of the latter 

 more sparse. Actinopharynx without spirocysts. 



Colour: salmon-red, with tentacles 'a little paler, or white. Reproductive organs white or sal- 

 mon-red. 



Dimensions: Length of the column to about 1,5 cm. Breadth of the oral disc to about 1,5 cm. 

 Diameter of the pedal disc to about i cm. 



Occurrence: Sweden. Gullmarfiord (Saltkallefiord, Skarbergen, Borsas, Orstadhufvud, Humle- 

 sacken) (Carlgren and others) from some few to 30 fathoms on Ascidiae, Serpula- and Chaetopterus tubes, 

 rather common. Koster Isl. E. off Hamnholmen 80 100 m. 



Norway. Christianiafjord, Drobak (Carlgren 1899) Hardangerfiord, Jonanes, Straumastein 100 

 400 m (teste Grieg), Oxen 100 150 fms. (Asb j or nsen, labelled A nthea cereus), Osterfiord (Appellof, 

 teste Grieg). Drontheimfiord, Roberg 200 400 m. (Arwidsson, Arndt and others) Skarnsund 100 

 200 m on Lophohelia (Oestergren, Arndt, Mortensen), Lofoten. Tysfiord 500 m on Lophohelia 

 (Nordgaard). 



