Trypomastigote

Trypomastigote is an extracellular "non-replicative" form of a parasite. It is a leaf-like form with undulating membrane and flagellum that emerges through a flagellar pocket and runs the whole length of the cell. A large kinetoplast is found at the base of the flagellum. Trypomastigote is found in the bloodstream of infected vertebrate host.

Reference: 1) http://dna.kdna.ucla.edu/parasite_course-old/Default.aspx

Seen in Trypanosoma cruzi and Trypanosoma brucei. Can be either metacyclic (in T. cruzi), procyclic, or blood stream form (both in T. brucei).