Initially, eggs Crassicauda sp. were found in the feces of the Pacific bottlenose dolphin (Tursiops truncatus gillii), which expands our knowledge of this nematode’s tropism, since crassicauda mainly inhabits the urogenital system or muscles. The material was volunteered from spontaneously infested 7-year-old female using a sterile disposable gastric tube Suyun (Unicorn Med) at Moskvarium. Feces were studied in the Center for Oceanography and Marine Biology laboratory (Moscow) by a direct smear method using Mikmed-5 light microscope (LOMO) and in the Laboratory for Study of Parasitic Diseases at the premises of the V.L. Yakimov Department of Parasitology of the St. Petersburg State Academy of Veterinary Medicine (St. Petersburg) using the crushed drop method and simple flotation method with Darling’s solution and further microscopy of temporary preparations in the Mikmed-6 light microscope (LOMO). Along with the morphometrically equal thickness of the multilayer egg membrane, the elongated part of the intact egg was optically inhomogeneous, which was even more noticeable in a damaged egg. Eggs with polar concavities of the inner layer and all of the layers of the membrane were found. The egg morphology indicates pliability of the polar structures of the membrane, which may be important when the larva emerges.

The Nasitrema sp. parasitization in the short-finned pilot whale (Globicephala macrorhynchus) was detected using intravital diagnostic methods for the first time. The material for the study was excreted content of the upper respiratory tract which was voluntarily obtained from the whale ("blow" to the Petri dish at the trainer’s command). The study was conducted in May of 2016 at the Moskvarium – Center for Oceanography and Marine Biology. Two individuals of the short-finned pilot whale were captured in Taiji Bay (Japan) in the autumn of 2014 and transferred to Russia by air in January of 2016. The animals were kept at the temporary base in the Gerasimikha village, Pushkin district, Moscow region. Ovoscopy was performed using the native smear and Mikmed-5 light microscope (LOMO) in the light field. Yellowish eggs with caps at one of the poles were found in samples from one of the pilot whales. They were identified up to the genus (Nasitrema) according to their morphology and epizootic data. The life cycle of Nasitrema has not yet been revealed; however, being a Digenea, it, probably, must be heteroxenic. Therefore, an infected pilot whale is not a danger to other individuals.