Ten specimens of Lates calcarifer Bloch commonly called apahap (Tagalog) bought from Central and Quiapo markets, Manila, Philippines, were examined for helminth infection. This species, also known as sea bass, is a marine fish which comes into brackish and fresh waters. The specimens were taken from brackish water fish ponds at Malabon, Rizal Province. One fish was infected with 3 metacercariae, 1 in muscle and 2 in the intestine. The new species herein described as Transversotrema laruei n. sp. has the characteristics of a fully developed worm except for the absence of eggs in the uterus. It resembles Cercaria koliensis Olivier.