Filiaria sanguinis hominis - mature form.

Lewis made the critical connection/association of the worm, Filaria sanguinis,(Wuchereria bancrofti ) to Elephantiasis. This brief account appears to be a third person account summarizing Lewis's work written by an editor of the Indian Medical Gazette. Digital facsimile from PubMedCentral at this link.

Lewis published a formal paper in Lancet: "Filaria sanguinis hominis (mature form), found in a blood clot in Naevoid Elephantiasis of the scrotum," Lancet, II (1877) 453-455.

(Thanks for Juan Weiss for these references.)