ACTINIARIA 



55 



Occurrence: Norway Finmark (Goe'sandMalmgren) 5 sp. Tromso2ofms. (Goes and Mai mgr en 

 3 sp. littoral (Kier) 3 sp. 



Exterior aspect: The physa is ampullaceous in extended state and perforated by apertures, the 

 number of which I have not been able to determine with certainty. In a specimen I observed such apertures 

 in 7 compartments. Probably they are arranged in a ring round a central aperture. The specimen from 

 Finmark, mentioned by myself as E.clavata (1893, p. 16), belongs to E.vitrea. The scapus is provided with a 

 thin periderm in which there are ochreous-coloured incrustations. The nemathybomes are very small, but 

 numerous and scattered. The sca- 

 pus seems to be smooth, because 

 the nemathybomes only rise a 

 little or not at all over the sur- 

 face, in contracted as well as in 

 expanded individuals. The proxi- 

 mal part of the scapus is almost 

 round, the distal part polygonal, 

 probably on account of the con- 

 traction. The capitulum is short. 

 The number of the tentacles va- 

 ries considerably. Of 5 examined 

 specimens one had 16, two 22, 

 one 23 and one 26 tentacles, ar- 

 ranged in two or three cycles. The 

 oral disc is small, the actinopha- 

 rynx short. A ventral siphonogly- 

 phe is present. 



Anatomical descrip- 

 tion: The nematocysts of the 

 physa are 12 14 p in length. The 

 apertures are surrounded by cir- 

 cular muscles. The numerous ne- 

 matocysts of the nemathybomes vary considerably in size, they are commonly 31 44 (* lon g> sometimes 

 shorter, down to 26 p, sometimes longer, unto 62 p. The ectoderm of the capitulum is rather thick, with sparse 

 nematocysts, 1012 p long. The high ectoderm of the tentacles contains numerous nematocysts (2226 X 2.5 

 3 p) and spirocysts (1417 p long). The ectodermal longitudinal muscles of the tentacles are rather well- 

 developed. The ectoderm of the actinopharynx is high and provided with several ridges; its nematocysts 

 are numerous, 3035 X 2.53 /< in size - The ectoderm of the siphonoglyphe contains very few nematocysts 

 and glandcells; its cilia are longer than in the other part of the actinopharynx. 



The imperfect mesenteries in the uppermost part of the column are rather strong. The longitudinal 



Fig. 65. Fig- 67- 



Textfig. 65 67. Edwardsia finmarchica. Transverse section of pennon (fig. 65) and of 

 parietal muscle (fig. 66) in the reproduction tract. Pig. 67 Transverse section of parietal 

 muscle in the lower part of the actinopharynx. 



