98 



ACTINIARIA 



Diagnosis: Nematocj'sts in the ectoderm of the column 25—29 (34) X 3,5 fi, in the tentacles 29 



39 X 4 — 5 [I, in the actinopharynx 29 — 41 X 4 — 5 fi, Spirocysts of the tentacles about 17 — 26 x 2,5 /i. 



Longitudinal muscles of the tentacles well developed. Conchula with three lobes, in extended state large, 

 in contracted more or less distinct. Muscle-pennons in the mesenteries of the first cycle strong, expanded 

 over almost the whole breadth of the mesenteries. The folds of the pennons rather high, in transverse-sec- 

 tions pectinate. Parietal muscles weak, not expanded on the column. Oral stomata and small marginal sto- 

 mata present. 



Colour: light puri)lish brown with bluish iridescence, similar to that of Cyanca arctica (Verrill). 

 The largest specimen was brownish, in alcohol. 



Dimensions: The largest specimens dissected by myself were 3,5 cm long and 2,5 — 3 cm broad; 

 the length of the tentacles about 0,9 cm. 



Occurrence: West-Greenland Egedesminde (Levinsen 1877) i sp., Nordre Stromfiord, St. 9 a 



(Nordmann) i sp., Greenland without distinct locality (Fasting). 

 Further distribution: North America from Cape Cod to Fundy bay. Nahaut Mass. to Eastport 



Maine (Verrill), Arctic ocean to Cape Cod (Parker) as larva on Cyanea 

 arctica, as adult at Eastport Maine (Verrill). 

 Exterior aspect: The specimens were rather well preserved. The form of the body was more or 

 less egg-shaped, according to a strong contraction of the distal and basal ends. The column is smooth with 

 somewhat distinct longitudinal furrows corresponding to the insertions of the mesenteries; besides these, 

 there are also transversal furrows produced by the contraction of the column. A distinct fossa is present. 

 The tentacles are short, cylindrical, with a porus in the apex, and more or less longitudinally sulcated, ac- 

 cording to the state of contraction. The number of the tentacles is 12. In the largest specimen one tentacle 



was invaginated. The oral disc is not particularly wide. The lobes of the con- 

 chula were indistinct in two specimens. In the largest specimen a little protube- 

 / ranee of the conchula is seen near the middle-line on one side; on the other side 

 4 a similar elevation is probably present, though I cannot confirm it with certainty 

 as the conchula was a Uttle damaged here. In the second specimen the conchula 

 was strongly contracted so that no distinct lobes are visible, in the third specimen 

 it was of the same appearance as on the figure given by Verrill (1864) (Fig. 125 a). 

 The actinopharynx is long, in proportion to the length of the body, and pro- 

 vided with a very well developed siphonoglyphe, the aboral prolongation of which 

 almost equals the length of the actinopharynx. The actinopharynx is longitudinal 

 and transversally sulcated, the transversal furrows are certainly a result of the 

 contraction. 

 Textfig. 125. Anatomical description: The ectoderm of the body-wall is high and 



Peachia parasitica. , . . . , . „. r .-i m. j n 



Fig, 125a seen from the oral thicker than the mesogloea. The stratum of nerve-fibnllae and nerve-cells are 



disc. /; conchula, s: siphono- distinct in the distal part of the ectoderm of the column; in the other parts it is 



glyphe. I"ig. 1256 seen from 



the side, after Verrill 1864. not SO much developed. I have measured the nematocysts (h) and the spirocysts 



