The collection contains permanent histological preparations of serial sections made from the whole animals or their parts and stained using Golgi-Colonnier silver impregnation method modified for each species by O.V. Zaitseva or using classic histological staining techniques with Heidenhain's azan and toluidine blue. A substantial portion of the collection consists of histological preparations immunostained for nervous elements containing serotonin, neurotensin, FMRFamide, and acetylcholintransferase and stained histochemically for catecholamines and NADPH-diaphorase (topographic marker of the neurons containing regulatory nitric oxide). The collection includes species of both nemertean classes (Enopla and Anopla). The preparations show the architecture of the nemertean nervous system, the structure of their CNS and sensory organs, and the nervous system of the body wall, proboscis and digestive tract and demonstrate the distribution of various regulatory substances in the peripheral and central nervous systems of different nemertean species. The preparations of each species stained with different methods (various numbers of microscope slides) are stored in separate numbered slide boxes in special storage cabinets located in the Laboratory of Evolutionary Morphology of the Zoological Institute RAS (ZIN RAS). Each slide is labelled with all essential identifying information. The collection was created at the Laboratory of Evolutionary Morphology of ZIN RAS.