. Text-fig. 32. Rosacea plicata. Larva from 'Research' (1900) St. 36^, Bay of Biscay. A, lateral view of whole larva, x6; B, larval nectophore, x 24; C, view of nectophore from aboral end, x 22. Thanks to the generosity of Dr Tregouboff, Director of the Station Zoologique at Villefranche, where so much of the pioneer work on Siphonophores was carried out, I have been able to examine a very well-preserved post-larva of Vogtia glabra (PI. IV, fig. 2; Text-fig. 33). It is identifiable because within the hydroecium of the larval nectophore is a young, definitive, heteromorph nectophore characteris

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. Text-fig. 32. Rosacea plicata. Larva from 'Research' (1900) St. 36^, Bay of Biscay. A, lateral view of whole larva, x6; B, larval nectophore, x 24; C, view of nectophore from aboral end, x 22. Thanks to the generosity of Dr Tregouboff, Director of the Station Zoologique at Villefranche, where so much of the pioneer work on Siphonophores was carried out, I have been able to examine a very well-preserved post-larva of Vogtia glabra (PI. IV, fig. 2; Text-fig. 33). It is identifiable because within the hydroecium of the larval nectophore is a young, definitive, heteromorph nectophore characteris
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Image ID: MCPE84
. Text-fig. 32. Rosacea plicata. Larva from 'Research' (1900) St. 36^, Bay of Biscay. A, lateral view of whole larva, x6; B, larval nectophore, x 24; C, view of nectophore from aboral end, x 22. Thanks to the generosity of Dr Tregouboff, Director of the Station Zoologique at Villefranche, where so much of the pioneer work on Siphonophores was carried out, I have been able to examine a very well-preserved post-larva of Vogtia glabra (PI. IV, fig. 2; Text-fig. 33). It is identifiable because within the hydroecium of the larval nectophore is a young, definitive, heteromorph nectophore characteristic of the species.1 Its identification is important because the larval nectosac shows clearly that only dorsal and ventral radial canals are developed at this stage in V. glabra, if my identification is correct. Both types of shed larval nectophores, i.e. with two and with four radial subumbral canals, have been found from time to time in plankton samples, and would constitute distributional records for the species concerned. In Chun's (18886) figures of Naples larvae he omitted the dorsal canal (inserted by Moser in a copy, 1925). R.R.S. 'Discovery II' has taken many dozens of post-larvae of Rosacea plicata measuring up to 12 mm. in length. There is a clear discontinuity between these and the smallest definitive nectophores. From this fact I deduce that the larval nectophore of R. plicata is caducous, as in Hippopodius. Moser (19240) figured larval nectophores of Rosacea cymbiformis, Vogtia serrata and V.pentacantha. The subjects of her plates (pi. 1, fig. 3; pi. 11, fig. 5; and pi. in, fig. 4) contained a young definitive nectophore, but the last two cannot be identified with much certainty. 1 Only two prominences are present above the nectosac and not four. In the larva from Orotava, attributed by Chun (i888«) to Hippopodius hippopus, he did not mention the number of prominences, but figured what looked like one of a pair only. But Chun's larva had four radial subumbral ca