Our sense of smell starts with molecular receptors expressed by neurons in our noses. The organization of olfactory systems has been intensely studied in vertebrates and in insects. However, little is known about the molecular basis for this sense in molluscs. We are studying the neuronal signaling pathways in the nudibranch mollusc, Berghia stephanieae. This can give us insights into evolutionary patterns and help us infer structural or functional constraints on how olfactory signals are processed. Berghia has olfactory organs called rhinophores that detect chemicals via G-protein coupled receptors (GPCRs). Odorants activate GPCRs, triggering G-proteins that initiate a chain reaction resulting in a neuron firing. Different types of G-proteins, most notably Gα, differ according to the receptor’s function. Identifying Gα variants, such as the smell-associated Gα-olf, is a convenient way to observe where olfactory signals are transmitted. Current work is focused on reconstructing phylogenetic trees of these proteins across molluscs to indicate evolutionary relationships between G-proteins in Berghia and other molluscs. As well as using single-cell RNA sequencing data, cell tracing, and HCR with confocal microscopy, to identify and classify the neurons and genes associated with olfaction. By characterizing olfactory neurons in these molluscs, we can provide a new perspective on olfactory-related proteins in this emerging study system for neuroscience.