ACTINIARIA 



219 



in S. tuberculata but not as high. Parietobasilar and basilar muscles and stomata as in 5. tuberculata. Nema- 

 tocysts of the tentacles as well as those of the actinopharynx very numerous, the former 31 38 X 2,5 /<, 

 the latter 19 29 X 2 (2,5) //. Spirocysts of the tentacles very numerous, from 24 X 2 p to 58 X 4 p. 



Colour in alcohol: uncoloured, actinopharynx brown. 



Dimensions of the largest specimen: Breadth of the pedal disc 4,5 X 3,5 cm, height of the body 

 about 2,6 cm, length of the inner tentacles 1,4 cm, that of the outer 0,5 cm. The smallest specimen was i cm 

 high and 2,2 X 1,5 cm broad. 



Occurrence: 6o37' N. 2 75 2 ' W. 799 fms. Bottom temp. 4,5 (Ingolf-Exp. St. 78) 9 specimens. 



Exterior aspect: The pedal disc is well developed, in contraction wrinkled. The column is like 

 that of the species, described above, sometimes there seems to be an indication of a margin and a fossa, it is, 

 however, probable, that they have arisen by contraction, as in one and the same individual such formations 

 appear in some parts, and are wanting in other parts. The tentacles are from cylindrical to conical, according 

 to the different state of contraction, in contracted state provided with irregular, transverse furrows and devoid 

 of abaxial thickenings at the base. The inner tentacles are at least twice as long and broad as the outer. They 

 are arranged in several cycles, but the agroupment is difficult to decide. The number of the tentacles was in 

 the largest specimen 71, in the smallest 74, and in a third 67. The tentacles occupy the greater part of the oral 

 disc which is provided with distinct, radial furrows. The actinopharynx is longitudinally sulcated, on account 

 of the bad preservation I cannot determine the number of furrows. The siphonoglyphes are distinct and 

 provided with aboral prolongations. 



Anatomical description: To judge from the small remaining fragments the ectoderm of the 

 column is low and contains rather numerous nematocysts, about 17 X 2 p in size. The mesogloea is very 

 thick, fibrillar, with scattered, protoplasma-poor cells. The sphincter is weak, takes up about one third of the 

 breadth of the mesogloea and shows a decidedly reticular structure as in Stomphia coccinea. The column, 

 however, seems to be able to cover tentacles, as they were indiscernible in one specimen. The endodermal 

 circular muscles are weak and form low folds. The ectoderm of the tentacles is not particularly thick and 

 contains very numerous nematocysts, 31 38x2,5 p in size, and Spirocysts from 24 X 2 p to 58 X 4 p. The 

 mesogloeal longitudinal muscles are strong and uniformly developed round about the tentacles and also at 

 the base. The muscle meshes are often elongated in radial direction. The mesogloea is thick. On a long- 

 itudinal section (textfig. 204) through the apex of a tentacle the mesogloea was much thinned out about the 

 aperture. If this thin lamella has been torn up by bad preservation, we may easily fancy that the apertures 

 of the tentacles were large. There is no doubt that the large apertures, observed by Hertwig in the tentacles 

 of Sicyonis crassa, have arisen through the at the apex very thin mesogloea having been partly macerated 

 by preservation. The radial muscles of the oral disc are very well developed and form closely packed meshes, 

 elongated in the direction from the ectoderm to the endoderm, and interrupted by thick mesogloea-bridges 

 at the insertions of the mesenteries. Its mesogloea is thick, like that of the actinopharynx. The ectoderm of 

 the actinopharynx is rather low, especially in comparison with the mesogloea, and contains very numerous 

 nematocysts: 19 29 X 2 (2,5) /j, in size, I have besides observed some larger nematocysts (34 36 X 2,5 /*), 

 which, however, possibly belong to the tentacles. 



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