ACTINIARIA 



Mediterranean namely indicates its cosmopolitism. It is true that the nematocysts differ a little in size and 

 occurrence from those of the Arctic and Antarctic specimens, but this difference is not so considerable as 

 to make us want to put up a new species; it is possibly a separate race or variety (mediterranca) to which 

 the not sexually ripe specimens, taken at the coasts of Bohuslan and Ireland, probably belong. 



Genus Acthelmis Lttlken. 



Diagnosis: Halcampoididae without sphincter. Column expanded, smooth, without papillae, not 

 divisible into regions or indistinctly so. Tentacles more than 12, not swollen in the apices. Siphonoglyphes 

 absent or very feebly developed. 6 pairs of perfect, fertile mesenteries with longitudinal pennons. Sterile, 

 imperfect mesenteries without pennons, in one or several cycles. 



Liit ken has for Actinia intestinalis Fabr. proposed the genus Acthelmis, but never given any diag- 

 nosis of the latter. In the Arctic regions there are two species, the only hitherto known. Probably the genus 

 Charisea, described by Torrey (1902), is synonymous with Acthelmis, though this author places this genus 

 to the family Actiniidae. The body-shape of Charisea namely indicates that the genus has no distinct pedal 

 disc, and the figures given by Torrey of the muscles of the mesenteries and his description of the rest of 

 the genus agree well with the above diagnosis of Acthelmis. It may besides be that the species C. saxicola 

 is identical with anyone of the here described species of Acthelmis. 



Acthelmis intestinalis (Fabr.) Liitken. 



PI. i. Figs. 6 7. 



Actinia intestinalis n. sp. Fabricius 1780, p. 350, figs, n A C. Andres 1883, p. 588. PFleming 1828, 



p. 498, PSars 1835, p. 3. ? Johnston 1847, p. 219, textfig. 49. PLandsborough 

 1852, p. 247. ? Norman 1868, p. 318. 

 A. (Acthelmis) intestinalis Fabr. Lutken 1875, p. 186. 

 Actinocereus intestinalis. Blainville 1830, p. 294, 1834, P- 3 2 $- 



Diagnosis: Column in the proximal end rounded or sometimes flattened. Division into regions 

 indistinct. Nematocysts of the column and tentacles 14 17 X 2 3 //. Spirocysts of the tentacles unto 

 22 X 3 ft. Tentacles 18 26 with feebly developed longitudinal muscles. Nematocysts with distinct basal 

 part to the spiral thread 17 22 X 4 5 fi in the ectoderm of the actinopharynx. 2 indistinct siphonoglyphes. 

 Pairs of mesenteries 6 + 6 + 12, the latter cycle more or less perfect. Folds of the longitudinal pennons 

 high, but not very numerous (on transverse-sections through the upper part of the reproductive region about 

 20, through the lower part about half the number) and ramificated mainly in the outer part. The lamellar 

 outer part of the mesenteries issuing from the outmost end of the pennon. Parietal muscles weak, but ex- 

 panded, with few, scattered, short and thin folds. Mesogloea in the parietal muscle-region thin. Expansion 

 of the parietal muscles on the body-wall inconsiderable. Longitudinal muscles of the imperfect mesenteries 

 of about the same structure as the parietal muscles of the perfect mesenteries, but a little stronger. Well 

 developed ciliated streaks. 



