. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. ACTINIARIA 203. Fig. 19 Fi<»- 194 number of tentacles is about 96 (6 + 6 + 11 + 24 + 48), the inner are many times larger than the outer. Sometimes the tentacles are indistinctly longitudinally sulcated. The oral disc is wide, its larger part has no tentacles. It is provided with indistinct radial furrows, corresponding to the insertions of the mesenteries. Actinopharynx is of ordinary length, irregularly wrinkled and provided with 2 deep siphonoglyphes. Anatomical description: The ectoderm of the col- umn is almost lost,
. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. ACTINIARIA 203. Fig. 19 Fi<»- 194 number of tentacles is about 96 (6 + 6 + 11 + 24 + 48), the inner are many times larger than the outer. Sometimes the tentacles are indistinctly longitudinally sulcated. The oral disc is wide, its larger part has no tentacles. It is provided with indistinct radial furrows, corresponding to the insertions of the mesenteries. Actinopharynx is of ordinary length, irregularly wrinkled and provided with 2 deep siphonoglyphes. Anatomical description: The ectoderm of the col- umn is almost lost, only a few fragments of it were present in several invaginations. In these fragments I found nematocysts, 14—17 X about I fi in size. Its mesogloea is thick and shows the same differentiation into two layers, an outer, provided with numerous cells and an inner, fibrillar and poor in cells, as that which I have described more in details for Sicyonis tuberculata. The endodermal circular muscles are weak, the distinctly longitudinally stratified sphincter, however, strong. In the uppermost part it occupies almost the whole breadth of the mesogloea, diminishes rapidly and passes into the endodermal circular muscles (textfig. 192, 193). The ectoderm of the ten- tacles is high with very numerous spirocysts (size: from 17x1 n to about 41 X 4,5 fi) and also rib-like typical nematocysts (size 22 X 2—31 X 2,5 //). Besides these, there are sparse nematocysts with discernible basal part to the spiral thread (size about 31— 36 X 3—3,5/^). The mesogloea of the tentacles is thinner than the ectoderm. The longitudinal muscles form numerous, closely packed, radially extended meshes in the mesogloea. On the outside of the outermost tentacles, lowermost at the base where the me- sogloea is a little thickened, the longitudinal muscles are lacking, the muscle-lacking part, however, being inconsiderable (textfig. 194). Not far from the base, scattered muscle fibres namely ap- pear, rapidly
Size: 1438px × 1738px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectscienti, bookyear1921
