40 



ACTINIARIA 





capituluni about 14 /i long. Tentacles 16. Nematocysts of the tentacles 19 — 26 X 2 — 2,5 /i, their spirocysts 

 12 — 24 X about 3/1. Nematocysts of the actinopharynx partly 29 — 41 X 3 — 3.5 ,«, partly (24) 26 — 34 x 

 4 — 6 ft, the latter with discernible basal part to the spiral thread. lyongitudinal muscle-pennons with few, 

 ID — 13 folds, only branched in the outer part. The outer lamellar part of the mesenteries attached to the 

 pennon next to the outside. Parietal muscles ordinarily developed, in transverse sections through the 

 distal part of the column looking like a half-opened fan. The expansion of the parietal muscles on the 

 column considerable. 



Colour in alcohol, rusty- to ochreous-coloured, in the distal part sometimes dirty-grey. 

 Dimensions in contracted state. I^ength to about 0.9 cm, breadth to about 0.35 cm. 

 Occurrence. East-Greenland. Mackenzie bay north of Franz Joseph's fiord 12 — 35 m mud (Sw.- 



Polar-Exp. 1900. N. 17) 2sp., Scoresby Sound Famae islands 70°5'N. 

 22°33' W.5 — 9 m mud (Sw.-Greenland-Exp. 1899 No. 32) 5 sp. South 

 M^s^ of the little Pendulum island 74°35' N. i8°23'W. 18 — 21 m mud and 



sand (Sw. Greenland Exp. 1899 No. 20) i sp. 

 Jan Mayen7i°i2' N.8°28' W. 1275 m grey clay (Sw. Greenland-Exp. 1899 No. 17) i 

 sp. (badly preserved and young specimen, determination dubious. 

 Nova Zembla Matotschkin Sharr 2 — 5 fms. clay and sand (Nova Zembla-Exp. 1875 



No. 80). 

 Kara Sea 73°38' N. 63°45' E. 80 fms. shells (Nordenskiold-Exp. 1876, No. 38) 2 sp. 



Exterior aspect. The physa is ordinarily developed and perforated by apertures. The scapus 

 is provided with a periderm, most developed in the proximal part, the distal part of the scapus is polygonal. 

 The nemathybomes are rather large, possibly a little irregularly arranged in the proximal part; in the distal 

 part they form an undulating row in the middle of each compartment. It is probable that the nemathybomes 

 are grouped in 8 longitudinal rows, but as all the animals were very strongly contracted this arrangement 

 may have been disturbed by the contraction. The capituluni is of usual appearance. The tentacles are 16 

 in number. The actinopharynx and the siphonoglyphe were not well preserved. 



Anatomical description. The ectoderm of the physa is high with scattered nematocysts, 10 — 14 ju 

 long. To the physa foreign bodies sometimes adhere. The ectoderm of the scapus is rather high with an or- 

 dinarily developed periderm, to which a great many foreign bodies are sticking. The nematocysts of the 

 nemathybomes are numerous. A general view of the size of the nematocysts of the examined specimens 

 shows as follows. 



in the (b) nematocysts of the actinopharynx the basal part to the spiral thread is discernible. 



