Discovery reports (1962) Discovery reports discoveryreports30inst Year: 1962 324 DISCOVERY REPORTS Nematocysts We do not yet know the whole story of the development, transport and thread-devagination of the nematocysts of Physalia. There are two distinct types of nematocyst. Those found in the tentacles have globular capsules and tapering threads or filaments (PI. XXV, fig. 4). The capsules are of two mean sizes, 26-8// and 11-3 fi in diameter (Lane and Dodge, 1958). That the threads taper can be seen both in optical section of the coiled-up threads and in devaginated ones. PI. XXV, fig. 5 s
Discovery reports (1962) Discovery reports discoveryreports30inst Year: 1962 324 DISCOVERY REPORTS Nematocysts We do not yet know the whole story of the development, transport and thread-devagination of the nematocysts of Physalia. There are two distinct types of nematocyst. Those found in the tentacles have globular capsules and tapering threads or filaments (PI. XXV, fig. 4). The capsules are of two mean sizes, 26-8// and 11-3 fi in diameter (Lane and Dodge, 1958). That the threads taper can be seen both in optical section of the coiled-up threads and in devaginated ones. PI. XXV, fig. 5 shows pads of these isorhizas round the mouth of a gastrozooid. Having no butt or hampe they should be referred to as isorhizas. Developmental stages can be found in the walls of the ampullae, from which they migrate not to the earliest formed pads or heads of the tentacle, but to those that have grown a little They can be seen during passage in the ectoderm of the tentacle-tube or lamella. Will (1909) figured the cnidoblasts of this type of nematocyst, and although I could not resolve all the details of those I have examined, I can confirm his account of them in general (Text-fig. 10). The nucleus and 004 mm 0
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