ACTINIARIA 



227 



Actinostola callosa Verr. 

 Urticina callosa n. sp. Verrill 1882 p. 224, 315. 



Actinostola callosa Verr. Verrill 1883 p. 57 PI. 7 fig. 2, 1883 b p. 515, 534. Carlgren 1893 p. 71 PI. i 

 figs. 17, 19. PI. 4 fig. i. PI. 8 fig. 3. PI. 9 figs. 5, 6 textfigures 18, 19. Parker 1900 p. 753 

 textfig. ii. 



atrostoma n. sp. Stephenson 1918 b p. 118 PI. 14 figs. 5, 7, 8. PI. 15 fig. 7, PI. 16 figs, n, 12, 

 16 20. PI. 17 figs, i 4. 



Diagnosis: Body in contracted state cylindrical or somewhat cup-like, generally much more high 

 than broad. Pedal disc not larger than the breadth of the column, in contracted state often excavated. Column 

 thick, cartilaginous, in younger specimens often smooth or with irregular furrows, in larger specimens with 

 tubercle-shaped, rather flat thickenings of the mesogloea in the upper part or over the whole surface. Margin 

 indefinite, often continuous with the base of the outer tentacles, not capable of involution. Sphincter mode- 

 rately long but narrow, non-concentrated, distinctly longitudinally stratified, reticular to alveolar. Tentacles 

 hexamerously arranged, in large specimens in 7 cycles, rugose, sometimes with rather large thickenings of 

 the mesogloea at the outside of the base, the inner tentacles several times thicker and longer than the outer. 

 These thickenings may appear only on the outer tentacles or on all. Longitudinal mesogloeal muscles of the 

 tentacles and radial muscles of the oral disc of variable size but mostly alveolar. Both mesenteries in the pairs 

 of the third cycle of about the same size. Parietobasilar muscles about two thirds of the length of the column. 

 Dioecious. Reproductive organs on the mesenteries from the third cycle. Nematocysts in the ectoderm of 

 the column (17) 19 24(29) X 1,5 2 (a, those in the distal part of the tentacles 22 36 X 1,5 2 p and 

 those of the actinopharynx 22 34 x 2 (i. Spirocysts of the tentacles from 24 X 2 to 72 X 4,5 5 ft. Large 

 stinging capsules in the ectoderm of the tentacles very few (36) 43 51 X 6 8 /*, scarce nematocysts with 

 discernible basal part to the spiral thread, in the actinopharynx 21 26 X 4 5 p. 



Colour generally salmon-coloured or orange, all parts often of nearly the same colour, body-wall 

 almost always pale salmon-coloured or buff, varying to deep salmon-coloured or orange-red with paler tu- 

 bercles, oral disc most often deep salmon-coloured, or generally of the same colour as the body, but of a 

 darker shade, with paler radii, the large lateral lobes of the lip like the disc, but darker, usually salmon-coloured 

 or orange-brown, the large gonidial grooves whitish or pale yellow, tentacles usually plain deep salmon- 

 coloured or orange-brown, with paler striae or reticulations (Verrill). Body-wall salmon-coloured, shading 

 off a little into blue with yellow-red furrows. Tentacles and the outer part of the oral disc yellow-red, inner 

 part of the disc like the body-wall. Actinopharynx and the gonidial tubercles reddish-brown, especially the 

 upper margin of the actinopharynx (Carlgren). Actinopharynx and the whole ectoderm reddish-brown 

 in alcohol (Michael Sars-Exp. St. 76). 



Dimensions: Large specimens often 16 to 18 cm in height, with the expanded disc 20 25 cm 

 broad, larger tentacles about 1,5 cm long and 0,5 0,6 cm broad (Verrill). The largest specimen, observed 

 by myself from the Ingolf- Expedition (St. 65), in contracted state: the expanded oral disc 13 cm, the strongly 

 contracted body-wall 11,5 cm in height. A specimen from Japan: height 12 cm, breadth 8 cm. 



29* 



