. 1 mm Text-fig. 5. Transverse section through a gastrozooid in the buccal region. Inset: an enlarged region, ec = ectoderm, = folded endoderm (secretory cells), = ectodermal gland cell, mes = mesogloea, nem = nematocyst. their mouths constricted, and their interiors filled with food matter. For reasons given below, intra- cellular digestion can be stated to take place at this stage. We know from Bodansky and Rose (1922) that various enzymes are produced in the gastrozooids, but we are still far from knowing which cells produce which enzymes. In addition to the gastrozooids, we have
. 1 mm Text-fig. 5. Transverse section through a gastrozooid in the buccal region. Inset: an enlarged region, ec = ectoderm, = folded endoderm (secretory cells), = ectodermal gland cell, mes = mesogloea, nem = nematocyst. their mouths constricted, and their interiors filled with food matter. For reasons given below, intra- cellular digestion can be stated to take place at this stage. We know from Bodansky and Rose (1922) that various enzymes are produced in the gastrozooids, but we are still far from knowing which cells produce which enzymes. In addition to the gastrozooids, we have to consider the palpons, which, from their structure, are clearly concerned in digestion at some stage in the life-cycle, even though they may not play an important role while the gonodendra are still attached to the parent colony. The gastrozooid of Physalia consists of two well-defined regions (Text-fig. 4) which will be referred to as the ' buccal' and ' basal' regions. The buccal region, consisting of the whole distal half of the zooid, can be spread out as a flat disk in feeding. The basal half is characterized by conspicuous pro-
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
