. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. DAVEXrORT: PROCESSES CONCERNED IN ONTOGENY. 179 penetrate between the blastomeres, so that it is difficult to tell which part of the embryo has been derived from the egg and which part by immigration. Compare the origin of the cutis in Echino- derms (K. & H., Fig. 195), in Mollusca (K. & H., Fig. 686), and in Vertebrates (M., Fig. 306), and of the intestinal and vascular musculature of Verte- brates (, Fig. 185). All of these processes have this in common, that mesen- chyme migrates to an organ —
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. DAVEXrORT: PROCESSES CONCERNED IN ONTOGENY. 179 penetrate between the blastomeres, so that it is difficult to tell which part of the embryo has been derived from the egg and which part by immigration. Compare the origin of the cutis in Echino- derms (K. & H., Fig. 195), in Mollusca (K. & H., Fig. 686), and in Vertebrates (M., Fig. 306), and of the intestinal and vascular musculature of Verte- brates (, Fig. 185). All of these processes have this in common, that mesen- chyme migrates to an organ — vessel, layer, or mass — and applies itself closely to it, sometimes even penetrating into the substance of the organ. 6. Transportation by Mes- enchyme has hitherto been observed in but few cases. The most remarkable instance of this process is found in the Doliolidae, where the buds pro- duced from a stolon are trans- ported over half the length and half the circumference of the body by means of mesen- chyme cells, and are finally deposited, in very regular or- der, on the appendage of the budding individual. (Figures 8 and 9.) By similar means, apparently, one end of the funiculus of the Bryozoan Cristatella is transported from the dorsal to the ventral surface of the corni, as I have attempted to show elsewhere. (Bull. Mus. Comp. Zool., XX. 142.) Fig. 8. Dorsal view of tlie posterior rart of a large Doliolum "; Shows the buds being transported from the ventral to the dorsal (and posterior) stolon. (See K. & H., Fig. 830.). J}or»«/ «/•;•„ Fig. 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
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