o ACl'INIARIA 



208 



ments. In spec. 2 the third and fourth cycles and 6 pairs of the fifth were fertile. The other pairs of the fifth 

 and sixth cycles were sterile and without filaments. 



Genus Parasicyonis n. gen. 



Diagnosis: Paractiidae with a well developed pedal disc. Body more broad than high. Column 

 thick, smooth, without tubercles. Margin tentaculate without fossa. Tentacles rather short but broad, robust, 

 in contractions wrinkled, the inner longer than the outer. Sphincter comparatively weak, so that the column 

 commonly does not cover the tentacles. L,ongitudinal muscles of the tentacles and radial muscles of the oral 

 disc mesogloeal. Two deep siphonoglyphes. Numerous perfect mesenteries. Mesenteries often a little irregularly 

 arranged, both mesenteries of the last sterile cycle sometimes differently developed, so that one mesentery 

 is perfect, another not, but not regularly arranged as in Actinostola. Number of mesenteries at least twice 

 as large as that of the tentacles. Only the mesenteries of the last cycle fertile. These mesenteries do not 

 reach the oral part of the column and are, like all the other mesenteries, provided with well-developed filaments. 



The genus Parasicyonis is certainly nearly related to Sicyonis, from which it is mainly distinguished 

 through the fertile mesenteries having well-developed filaments with ciliated streaks, while in Sicyonis they 

 are devoid of such, though they are sometimes rather well developed. Also the arrangement of the mesenteries 

 seems to be different in both genera. Possibly it may later on be found out that they may be placed together 

 to a genus, for the present I consider it the most practical to separate them. Excepting the type, P. sarsii, 

 I place to the genus also P. actinostoloides and P. maxima, described by Wassilieff (1908) as belonging to 

 the genus Cymhactis. The whole of their exteriors namely recalls that of P. sarsii, and the imperfect description, 

 given by Wasilieff , in no way contradicts that we have to do with specimens of the genus Parasicyonis. 

 According to me, the following specimens belong to the genus: 



Parasicyonis sarsii Carlgr. 



— actinostoloides (Wassil.) Carlgr. 



— maxima (Wassil.) Carlgr. 



Parasicyonis sarsii n. sp. 



PI. 3. Fig. 12. 



Diagnosis: Sphincter reticular, thin but rather long, often in the outer parts with traces of strati- 

 fication. Tentacles commonly 86 to 103. About one half of the oral disc devoid of tentacles. Radial muscles 

 of the oral disc interrupted at the insertions of the mesenteries, strong. Number of mesenteries about twice 

 as many as the tentacles, or more. Mesenteries of the three first cycles and one part of the fourth perfect. 

 Part of these latter consisting of a perfect and an imperfect mesenterv'. Arrangement of the mesenteries 

 hexamerous but not regular. Longitudinal muscles of the mesenteries rather weak. Parietobasilar muscles 

 broad, but weak. Nematocysts in the ectoderm of the tentacles numerous (26)29 — 43 X 2 — 2,5 //, in that of the 

 actinopharynx 19 — 29(37) x 2 (1,5 — 2 (i). Spirocysts of the tentacles (14 X 1,5) 22 X 1,5 — 67 X 3,5 — 4,5 {i. 

 Nematocysts with discernible basal part to the spiral thread in the actinopharynx 23 — 31 X 3,5 — 4,5 //. 



Colour: pale brick-red, shading off into orange (spec, from Drontheimfiord , Carlgren). 



Dimensions of the two largest specimens: length 4 cm, breadth of the pedal disc 8 cm, length of 



