• (a.) Pertaining to the Siphonostomata. • (a.) Having the front edge of the aperture of the shell prolonged in the shape of a channel for the protection of the siphon; -- said of certain gastropods.
Si`pho·no·stom'a·tous adjective (Zoology) (a) Having the front edge of the aperture of the shell prolonged in the shape of a channel for the protection of the siphon; -- said of certain gastropods. (b) Pertaining to the Siphonostomata. 
siphonostomatous With tubular mouth; having front margin of shell notched for emission of siphon.