Аннотация:The organization of the nervous system in larvae and adults is traditionally used for phylogenetic study of many different organisms and may increase our understanding of phoronid relationships. Development and organization of larval nervous system are studied in larvae viviparous phoronid <Phoronis embryolabi>. Lateral nerves of the preoral lobe are the first 5ht-lir nerves to appear. The apical organ of competent larvae lacks multipolar perikarya. Competent larvae have three additional sensory organs and lack a minor nerve ring. The bauplan of the larval nervous system in phoronids includes the apical organ, two nerve tracts under the preoral and postoral ciliated bands, and two lateral nerves extending between the apical organ and the preoral nerve tract. The larval tentacular main nerve ring is regarded as the juvenile characteristic and is a peculiarity of some phoronid larvae and larvae of lingulid brachiopods. Although many characteristics of the organization of the apical organ are similar in phoronid and deuterostomian larvae, the general bauplan of the nervous system of phoronid larvae seems to be more similar to that of protostomian larvae. The similarities in innervation of the preoral lobe among different phoronid larvae may correlate with the similarity of the fate of the preoral lobe during metamorphosis, and the differences in the innervation of larval tentacles can be explained by the different ways in which the definitive tentacles form among phoronids. The presence of many sensory fields in larvae of the viviparous phoronid <P. embryolabi>, which live as commensals of burrowing shrimps, may correlate with the challenges that pre-metamorphic larvae presumably face in finding the burrows of shrimps. Study is supported by RFBR (17-04-00586).