. Carnegie Institution of Washington publication. Le jo Pluteus Laganum sp. 135 encerclant une région légèrement en avant du centre, sous laquelle se trouve l'anneau de l'hydroccele. Ici, donc, la bouche adultes est évidemment à la forme. La paroi de la cavité amniotique est composé de 2 couches de tissus qui sont en continuité les uns avec les autres autour de l'ouverture externe. Ils se composent d'une couche intérieure de grandes cellules irrégulières, et d'un épithélium de cellules cylindriques avec des noyaux de coloration sombre, généralement situées bien en arrière vers la base de la cellule. Dans la couche intérieure le cytoplasme est clair, et tak

• Contributeur: Book Worm / Alamy Banque D'Images
• ID de l’image: RFRKHE
• Taille du fichier: 7,1 MB (507,3 KB Téléchargement compressé)
• Autorisations: Modèle - non | Propriété - non
• Dimensions: 1779 x 1404 px | 30,1 x 23,8 cm | 11,9 x 9,4 inches | 150dpi

Informations supplémentaires

Cette image appartient au domaine public, ce qui signifie que le droit d’auteur a expiré ou que le titulaire du droit d’auteur a renoncé à ses droits. Les frais facturés par Alamy couvrent l’accès à la copie haute résolution de l’image.

Cette image peut avoir des imperfections car il s’agit d’une image historique ou de reportage.

. Carnegie Institution of Washington publication. The Pluteus oj Laganum sp. 135 encircling a region slightly anterior to the center, beneath which lies the ring of the hydroccele. Here, then, the adult mouth is evidently to form. The wall of the amniotic cavity is composed of 2 layers of tissue which are continuous with each other around the external opening. They consist of an inner layer of large irregular cells, and an outer epithelium of cylindrical cells with darkly staining nuclei, usually situated well back toward the base of the cell. In the inner layer the cytoplasm is clear, and takes the form of a loose, irregular meshwork; in the outer it is opaque and is crowded with pigment granules exterior to the row of nuclei. Occasionally, however, large areas may be found in the outer layer, within which the cytoplasm contains many irregular vacuoles, indicating that possibly the wall of the amniotic cavity is beginning to break down.. FIG. 17.—Transverse sec- tion through anterior part of body, showing two anterior primary tenta- cles, a.c., anterior en- teroccjele; P, I3, lumen of lobes 2, 3, of hydrocoele; sp, spine; t2, t3, tentacles 2, 3. X 233. 17 Histologically, the spines also are composed of 2 layers of tissue. The inner central one forms a core in which the cytoplasm possesses a large irregular meshwork. In the outer the cytoplasm is denser and crowded with pigment granules, and the nuclei stain more heavily with the hematoxylin. Between these two layers lie well-developed longitudinal bands of muscle. Within the spines were originally the skeletal supports described above, which have been destroyed in these specimens by the fixing fluid. THE ENTEROCCELES. Within the embryo, transformation from larva to adult is already beginning to take place. The gut has lost its opening to the exterior, the left posterior enteroccele is definitely constricted from the anterior, and the hydrocoele with its 5 primary tentacles is already in an ad- vanced stage of dev

Recherche dans la banque de photos par tags

• bookauthorcarnegie
• bookcentury1900
• bookdecade1900
• bookyear1902