Meeting Abstract

P2.74  Friday, Jan. 4  The Functional Morphology of Murray�s Organ in Tritonia diomedea OHMES, Lucas B*; TRUMAN, Gary A; CAIN, Shaun D; Eastern Oregon University; Eastern Oregon University; Eastern Oregon University ohmesl@eou.edu

The lateral tips of the oral veil in nudibranch mollusks serve as a primary sensory organ, derived from the anterior tentacle of the ancestral gastropod. This organ is thought to detect water-borne odors and water currents. In the sea slug Tritonia diomedea, this organ is innervated by a pair of peptidergic giant neurons (left and right pedal 7) that appear to function in the control of motor cilia on the ventral surface of the lateral tip. In this study we used a combination of histology, scanning electron microscopy, and confocal microscopy to investigate the morphology and innervation of this sensory organ. The most prominent structure on the lateral tip is a dense field of cilia that lines a groove on the ventral surface. These cilia are motor in structure and have been observed to beat in a direction that transports water from the tip of the cilia through the channel the proximal surface of the oral veil. Several types of ciliated cells line the edge of the groove; these cells likely function as either mechanoreceptors, chemoreceptors, or both. Histological and immunohistochemical studies further discriminate the ciliated cells into motor and sensory cells. Our findings suggest that the motor cilia of this organ move water through the groove of the lateral tip, moving odorants from the substrate to the chemoreceptor organs that line the groove. In addition, a second function of movement of the motor cilia might be to increase the effectiveness of the sensory cilia, analogous to antennule flicking behavior in crustaceans.