250 PROFESSOR OSKAR CARLGREN ON THE GENUS PORPONIA 



of the later developmental stages, yet it has to be noted that the position of the 

 tentacles, especially in Porponia, is difficult to determine, and it is just possible that 

 the agreement is somewhat greater than is represented in the schematic figures. 



While Halcurias and Porponia are thus closely related to each other, there is still 

 the question whether they have any near relationship to the genus set up by R. HERTWIG, 

 Antheomorphe, as M'MuRRicn and HERTWIG maintain, the one for Halcurias, the other 

 for Porponia. In my opinion, such a relationship does not exist, for Antheomorphe, 

 according to HERTWIG'S poor description of this genus, appears to have normally arranged 

 mesenteries and tentacles. On the other hand, it is not impossible that Halcurias and 

 Porponia are related to the form which WASSILIEFF (1908) has described as Ilyanthopsis 

 elegans. The abnormal development of the mesenteries in Ilyanthopsis elegans, ac- 

 cording to the obviously imperfect data given by WASSILIEFF, indicates, namely, the 

 possibility of a mesenterial arrangement such as in Halcurias and Porponia, and even 

 the habitus of the animal resembles that of Halcurias. To settle this, I have obtained 

 a specimen of Ilyanthopsis elegans for investigation from the Conservator of the Bavarian 

 State's collection in Munich. As WASSILIEFF'S description of the animal leaves much to 

 be desired,* and as it is by no means so schematically constructed as this author believed, 

 I give here a description of this species, a description, however, that cannot be considered 

 complete, as the material, which could not be dissected, was insufficient for the purpose. 



The body in Ilyanthopsis elegans is elongated, cylindrical, the base distinctly 

 flattened, but the boundary between body-wall and base not sharply marked. The 

 body-wall is provided with irregular transverse and longitudinal furrows, so that the 

 parts of the wall between the furrows have the appearance of raised areas, which, how- 

 ever, do not differ in their structure from the remaining part of the body-wall. The 

 tentacles are of moderate length, 2-2'5 cm. (length of body over 6 cm.), and distinctly 

 furrowed longitudinally, not thickened at the base and gradually narrowing towards 

 the distal end. The arrangement of the tentacles was difficult to determine and by no 

 means so simple as WASSILIEFF imagined. There is no arrangement into two circlets 

 only ; on the contrary, the arrangement shows distinctly a certain resemblance to that 

 in Halcurias and Porponia, as some displacement of the tentacles has taken place, 

 here also assuredly connected with an irregular arrangement of the mesenteries. In the 

 first place, we have in each angle of the mouth (in the sagittal plane) quite the same 

 arrangement of the tentacles as in Porponia and Halcurias. They further agree in 

 this, that at certain points groups of tentacles occur, where two tentacles of the first 

 order stand on each side of one of the second order. Lastly, the other tentacles also 

 show a resemblance in arrangement to the corresponding tentacles in these genera. 



* The Actiniaria described by WASSILIEFF, especially some of the species, require revision. Thus, the Actinia 

 described by WASSILIEFF under the name of Halciimpellu minuta is quite certainly no Halcampella-, but rather a 

 Halodava. The occurrence of warts and the appearance and structure of the tentacles, which are bulb-like and swollen 

 at the tips, speak in favour of this. The arrangement of the mesenteries and the siphonoglyphe agree less definitely, 

 but this may be due to the specimen being a young individual, as is indicated by the small number of tentacles (15). 

 If it cannot be referred to Halodava or Eloactis, it may represent the type of a new genus. 



(ROY. soc. EDIN. TRANS., VOL. L., 58.) 



