Archive image from page 84 of The Danish Ingolf-Expedition (1921). The Danish Ingolf-Expedition danishingolfexpe0509ingo Year: 1921 ACTINIARIA 77 basal part to the spiral thread. The uppermost part of the column is provided with distinct, though weak longitudinal muscles, forming a continuous layer in the tract where the spirocysts are common, but soon disappearing. A nerve-layer with nerve-cells is present and is the most developed in the uppermost part of the column. The mesogloea of the column is composed of alternate layers of longitudinal and circular fibrillae. The endodermal circular m
Archive image from page 84 of The Danish Ingolf-Expedition (1921). The Danish Ingolf-Expedition danishingolfexpe0509ingo Year: 1921 ACTINIARIA 77 basal part to the spiral thread. The uppermost part of the column is provided with distinct, though weak longitudinal muscles, forming a continuous layer in the tract where the spirocysts are common, but soon disappearing. A nerve-layer with nerve-cells is present and is the most developed in the uppermost part of the column. The mesogloea of the column is composed of alternate layers of longitudinal and circular fibrillae. The endodermal circular muscles form no special sphincter, but are rather well developed; in the proximal part, close by the proximal end, they are a little stronger than in the other parts. Tlie nmscle-folds are besides of different appearance, according to the state of contraction. The tract, corresponding to the region of the tentacles and the oral disc in other Actiniaria, is provided witli a remarkably Irigh ectoderm, several times higher than that of the column. The outer parts of this ectoderm consists, as a transverse-section through the oral disc shows (textfig. 93), almost exclusively of extraordinarily numerous, \'ery closely packed spirocysts, 19—36/.«i-'i cells of the spirocysts, and spirocysts in development. The ner\-e-layer is not ver>' distinct, on account of the immense number of stinging capsules. The radial muscles of the oral disc are weak and its mesogloea thin. The ectoderm of the actinopharynx is several times thicker than the mesogloea, here and there sending out irregularly pla- ced tongues towards the lumen of the actinopharynx. The nematocysts of the actinopharynx ectoderm are broader in the basal end than in the distal one, and the basal part to the spiral thread is perceptible; their size is about 24—26x4 [i. Also in the actinophar>'nx there are longitudinal muscles, though weak, but distinct, especially in the aboralpart. The actinopharynx is provided Textfig.
Size: 1281px × 1562px
Photo credit: © Actep Burstov / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: 1920, 1921, archive, arctic_ocean, book, bookauthor, bookdecade, bookpublisher, booksponsor, booksubject, bookyear, copenhagen_h_hagerup, danish_ingolf_expedition_1895_1896_, drawing, historical, history, illustration, image, ingolf_cruiser_, mblwhoi_library, page, picture, print, reference, scientific_expeditions, vintage, zimmermann_a_albrecht_b_1860
