134 



ACTINIARIA 



Andwakia mirabilis Dan. 

 Andwakia mirabilis n. sp. Danielssen, 1890, p. 86, PI. 4, figs. 10 n, PI. n. Appellof 1893, p. 12. 



Diagnosis: Physa ampullaceous, probably without papillae, as for the rest like the scapus. Scapus 

 with a cuticle and very distinct "Halcarnpa-papillae". Capitulum in contracted state with high ridges be- 

 tween the insertions of the mesenteries. Sphincter elongated, about twice as long as the capitulum, not stra- 

 tified, not forming an offset. Tentacles about 24 in three cycles. Nematocysts in the scapus 13 17 X 2 p, 

 in the capitulum 17 18 X 2,5 //, in the tentacles 19 24 u and in the actinopharynx 19 22 X 2 p. Spiro- 

 cysts of the tentacles 17 X 2 29 X 3,5 (i. 12 pairs of mesenteries. Muscle-pennons in transverse-sections 

 through the upper part of the reproductive region with about 20 high folds which are richly ramificated 

 and slightly recalling a circumscribed sphincter. Parietal muscles comparatively weak with few folds, not 

 expanded upon the column. Muscles of the mesenteries of the second order recalling the parietal muscles 

 of the mesenteries of the first cycle. 



Colour according to Danielssen: The scapus brownish-black, dotted with partly white, partly 

 green and reddish points. The capitulum faintly salmon-red, occasionally purely white with a fine rose- 

 coloured tinge. The oral disc cinnabar-red with fine, darker lines. The tentacles of the same colour but some- 

 what darker at the base, lighter at the apex. 



Dimensions in extended state: I/ength of the body 6 7 cm, breadth in the distal end 1,5 cm, 

 in the proximal end 0,4 0,5 cm. Length of the capitulum 0,8 cm, breadth of the oral disc 1,2 1,4 cm 

 (Danielssen). - - In preserved state to about 2,5 cm long. 



Occurrence: Norway. Sognefiord. Huson 100 150 fins. Sand (Norw. North- Atl.-Exp., Grieg, 

 1889), Hjelte fiord (Appellof). 



Exterior aspect: The proximal part of the body, the physa, is ampullaceous or flattened and, 

 as it seems, but little differentiated from the scapus. As on the scapus the ectoderm is here furnished with 

 a cuticle? (compare below) to which detritus-particles are fastened; it seems, however, that this cuticle is 

 more easily thrown off than that of the scapus. Probably there are no "Halcampa-papillae" here. The scapus 

 is elongated, narrow in the proximal part, more broad in the distal part, and set with numerous "Halcampa- 

 papillae" to which grains of sand are attached. The capitulum is short, without a cuticle and in contracted 

 state provided with high ridges and deep furrows, the latter corresponding to the insertions of the mesen- 

 teries. The body is in extended state cornucopia-shaped (Danielssen), in contracted state cylindrical. 



The tentacles are 24, arranged in three cycles, short, conical or cylindrical, according to the state 

 of contraction. The inner tentacles are a little thicker than the outer ones. The oral disc is not broad, the 

 actinopharynx rather short, in preserved state with irregular longitudinal and transversal folds. Two, not 

 very distinct siphon oglyphes are present. 



Anatomical description: The ectoderm of the physa is rather high and contains somewhat 

 numerous nematocysts of the same appearance and size as in the ectoderm of the capitulum. At the outside 

 it is surrounded by a thin covering, imbued with detritus-particles, this is possibly a cuticle but more prob- 

 ably a mucus-membrane secerned by the mucus-cells. The mesogloea of the physa is much thinner than 

 its ectoderm. The ectoderm of the scapus is thinner than that of the physa and contains nematocysts, 13 



