212 ACTINIARIA 



Mis-species. Manifestly a reversed case takes place, compared with Sicyonis, here we find the mesenteries 

 to be more numerous in the distal than in the proximal part, there they are more numerous in the proximal 

 part, here we probably find a greater number of tentacles, corresponding to the richer development of the 

 mesenteries in the distal body-end, there fewer tentacles in number, corresponding to that of the sterile me- 

 senteries. The arrangement of the mesenteries is, besides, so imperfectly known that we cannot with certainty 

 place this species in the vicinity of the genus Sicyonis, though much in Hertwig's description speaks 

 for it. For the present I should like to propose a new genus Synsicyonis for Sicyonis clongata, which I pro- 

 visionally characterize as follows: 



Paractiidae with the basal disc not enlarged. Column thick, cartilaginous, smooth. Sphincter, ten- 

 tacles, oral disc and siphonoglyphes as in Sicyonis, the number of tentacles, however, about the same as that 

 of the mesenteries. Arrangement of the mesenteries probably recalling that of Sicyonis (or of Actinostola?} 

 but irregular "owing to the alternation of isolated genital mesenteries with isolated complete ones." Mesen- 

 teries differentiated in stronger sterile and weaker fertile ones, the latter only in the distal part and without 

 filaments. 



According to me, the following species may be referred to the genus Sicyonis: 



S. crassa R. Hertw. 



5. gossei (Steph.) Carlgr. 



S. tubcrculata Carlgr. 



S. ingolfi Carlgr. 



5. variabilis Carlgr. 



Sicyonis tuberculata n. sp. 



PI. 3. Figs. 23. 



Diagnosis: Body, according to the different state of contraction, flat or more cylindrical, commonly 

 not high. Sphincter rather well developed, sometimes weak with groups of small meshes, encircled by stronger 

 stripes of mesogloea. Tentacles about 64 to 68 with very strong, swollen mesogloea on the base of the outside. 

 Apertures in the apex of the tentacles small. Longitudinal muscles of the tentacles on the inner side divided 

 in closely packed, but large, meshes, on the outer side considerably weaker and disappearing at the base. 

 Radial muscles in the outer part of the oral disc developed as on the inner side of the tentacles, interrupted 

 at the insertions of the mesenteries. Actinopharynx longitudinally sulcated. Siphonoglyphes very elongated 

 towards the aboral end. Pairs of mesenteries about 64 68, of which one half stronger, sterile and with well 

 developed filaments and longitudinal muscles, the other half alternating with these latter, with weak muscles, 

 fertile, generally without filaments, and extended only in the proximal parts of the body, from which they 

 reach a longer or shorter way upwards, in as much as the reproductive organs are more or less developed. 

 Commonly 16 pairs of perfect mesenteries. The rest of the filamentous pairs often symmetrically arranged 

 on both sides of the directive plane, but the arrangement is not regular as some mesenteries of one and the 

 same cycle arise earlier in certain exocoels than in others. Mesenteries of the pairs mostly differently developed, 

 some of them reaching the actinopharynx with only one mesentery of each pair. Longitudinal muscles of 



