The pictures are not clear. You should take a picture of the total body of the parasite. Then list in your question the scientific name of the host, the sight of infection and the habitat of the host. if you can prepare a permanent slides for the parasites, that is better. Good luck
First of all identify by key. Another method is fecal culture, for example Harda and Murray culture for carnivores, which ultimately identify the cultured infant parasite and diagnose with their posterior end and tail.