. Bulletin of the British Museum (Natural History). 5IO EVOLUTIONARY TRENDS IN CAPITATE HYDROIDS AND MEDUSAE Halocordyle tiarella (Ayres) Halocordyle, better known as Pennaria, has an exceptionally well developed, upright, branched hydrocaulus with regular branching and possessing ringed perisarc at the origins of branches (Text-fig. 25, p. 474). As regards this feature it is more advanced than any member of the related family Corjoiidae. Its hydranth is however little removed from the basic type of Corymorphine and its ancestor might well have been something rather Uke the larval Corymorpha n
. Bulletin of the British Museum (Natural History). 5IO EVOLUTIONARY TRENDS IN CAPITATE HYDROIDS AND MEDUSAE Halocordyle tiarella (Ayres) Halocordyle, better known as Pennaria, has an exceptionally well developed, upright, branched hydrocaulus with regular branching and possessing ringed perisarc at the origins of branches (Text-fig. 25, p. 474). As regards this feature it is more advanced than any member of the related family Corjoiidae. Its hydranth is however little removed from the basic type of Corymorphine and its ancestor might well have been something rather Uke the larval Corymorpha nutans, the only essential difference in external morphology of the hydranth being the addition of scattered capitate tentacles between the oral capitate whorl and the aboral filiform whorl (Text-fig. 53). In the latter these aboral filiform tentacles are fully developed and are not reduced in any way. The fully developed medusa is without tentacles and is seldom freed. Its structure is essentially Fig. 53. Halocordyle tiarella (Ayres) with female medusa bud still attached (redrawn from Mayer, 1910). Stauridiosarsia producta (Wright) In this colonial Corynid there is a creeping stolon but the upright hydrocaulus is poorly developed. Here the hydranth has an oral whorl of capitate tentacles, scattered capitate body tentacles and a reduced whorl of aboral filiform tentacles (Text-fig. 10). These reduced filiform tentacles reflect the trend in the Corynidae where the filiform tentacles are lost (see p. 462). The medusa has four radial canals, four perradial marginal tentacles, a ring gonad and simple mouth. AU these are primitive features, and, together with the ocellus on each tentacle, are typical of Sarsiid medusae. The tentacles of this and other. 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 Bri
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