Comparative analysis of Dendrocometes paradoxus Stein, 1852 cell morphology from various gammarid amphipod species in different regions of Ukraine, and those attached to several host body parts of Hyalella azteca collected in two Mexican lakes, was carried out in order to demonstrate the morphological variability, due to the hosts species or their geographical distribution. For hosts species and corporal distribution, no significant differences between the two populations were shown. As the result, it was found the suctorians common for amphipod crustaceans from Ukraine and Mexico all are conspecific and belong to D. paradoxus.
Apsectus kaliki sp. n. from Guyana is described, illustrated and compared with all the known Neotropical species of the genus Apsectus LeConte, 1854. Lectotypes are designated for Apsectus centralis Sharp, 1902 and Apsectus hystrix Sharp, 1902