Laboratory observations on the life history ofRhopilema verrilli(Scyphozoa: Rhizostomeae)
✍ Scribed by D. R. Calder
- Publisher
- Springer-Verlag
- Year
- 1973
- Tongue
- English
- Weight
- 633 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0025-3162
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✦ Synopsis
The life history of the scyphozoan Rhopilema verrilli is described from the planula to the young medusa stages. Planulae are retained within the gonadal tissue of the medusa until fully developed. On liberation, most planulae set and developed into small scyphistomae within 7 to i0 days. The scyphistoma differs from those of other described species in having an unusually large, clavate manubrium. The only means of asexual reproduction observed in the scyphistoma cultures involved the formation of podocysts. Strobilation was usually of the monodisc variety, although polydisc strobilation was not infrequent. The process of strobilation was completed within 7 days at 20~ Newly liberated ephyrae typically had 8 pairs of lappets, and 8 rhopalia. Ephyral development resembled that of the closely related rhizostome Rhizostoma pulmo. The cnidome of the planula and seyphistoma consisted of atrichous isorhizas ("a" atrichs) and microbasic heterotriehous euryteles, while that of the strobila and ephyra consisted of "a" atrichs, euryteles, and holotrichous haplonemes