Nudibranchs, a type of predatory sea slug, can have various protuberances (that is, extensions) on their dorsal surfaces. rhinophores are paired structures, located close to the head, which bear many chemoreceptors. dorsal plumules, usually located posteriorly, perform respiratory gas exchange. cerata usually cover much of the dorsal surface and contain nematocysts at their tips. if nudibranch rhinophores are located at the anterior ends of these sea slugs, then they contribute to the sea slugs'