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Distribution Of Bipinnaria And Pilidium In Relation To Physical Structure And Uv-B Light In The Water Column Off Anvers Island, Antarctica, William Jaeckle
Distribution Of Bipinnaria And Pilidium In Relation To Physical Structure And Uv-B Light In The Water Column Off Anvers Island, Antarctica, William Jaeckle
Scholarship
Feeding larvae of Antarctic bottom invertebrates have proven to be scarce in the plankton and consequently our knowledge of their ecology is limited. We collected bipinnaria larvae assignable to the genus Odontaster and several types of pilidium larvae of nemertean worms in quantitative net tows taken during the austral spring and summer 1997-1998 and considered their distribution with respect to the density stratification of the water column and the potential exposure to UV-B (λ = 308 nm). The average number of pilidium and bipinnaria larvae in the upper 40 m of the water column was 0.5 ± 1.0 per m3 …
Coelomogenesis And Nutrition Of Clonally Produced Asteroid Larvae, William Jaeckle
Coelomogenesis And Nutrition Of Clonally Produced Asteroid Larvae, William Jaeckle
Scholarship
Asexual reproduction by planktotrophic larvae of asteroids is an unusual life history strategy exhibited by several species in the families Luididae, Oreasteridae, Ophidiasteridae, and Asteriidae. Larvae of the former three families reproduce asexually in the field, while the asteriid Pisaster ochraceus has produced clones when larvae are reared in the laboratory. Our knowledge of the processes involved in larval cloning and the biology of the developing clone is fragmentary in nature. We used light, electron, and scanning laser confocal microscopy to study clones that develop through paratomy of the posterolateral larval arms. The archenteron forms by a modified form of …