. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Fig. Fig. 3. h. Next we must consider the aggregation of mesenchyme into a superjicially extended body, — the formation of a layer. Tliis process does not seem to be very common; one example is seen in Figure 4. c. As the last of these processes of aggregation we have the case of aggregation into a mass. This wide-spread ontogenetic process may be ilhistrated by the formation of gemmules in a marine sponge (P^igure 5). Other examples are found in the formation of the adductor muscles of J Fig. 3. Cross section of
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Fig. Fig. 3. h. Next we must consider the aggregation of mesenchyme into a superjicially extended body, — the formation of a layer. Tliis process does not seem to be very common; one example is seen in Figure 4. c. As the last of these processes of aggregation we have the case of aggregation into a mass. This wide-spread ontogenetic process may be ilhistrated by the formation of gemmules in a marine sponge (P^igure 5). Other examples are found in the formation of the adductor muscles of J Fig. 3. Cross section of a rat embrj-o in the upper thoracic region, showing the development of the sympathetic nerve (between spinal nerve and carotid artery). From A. M. Paterson, '91, Trans. Roy. Soc. Lond., PI. XXII. Fig. 4. Fig. 4. Later stage of the embryo shown in Figure 1. Tlie migrating proto- plasm lias aggregated itself into a layer at the surface of the embryo. See K. & II., Fig. 449. Fig. 5. Section of a marine sponge (Esperella), showing a gemmule, a mass of aggregated mesenchyme which is about to produce a gemmule (!'), and migrating, not yet aggregated mesenchyme (1). After H. V. Wilson ('94, Jour, of Morph., IX. Pi. XIV.).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
Size: 1562px × 1600px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorha, bookcentury1800, bookdecade1890, booksubjectzoology
