Siphonochelus tityrus: Shell small, composed of 1,5 bulbous nuclear whorls followed by five postnuclear whorls. Color rusty brown or pink, the varices white except for a patch of color at the base of the tubes. Interior of aperture flushed with pink. Four smooth, thick, somewhat reflected varices per whorl, without any trace of varical expansion, extending upward to meet the corresponding varix of the preceding whorl. Tubes directed apically, strongly recurved, forming a stout, tapered, hollow spine incorporated in the shoulder of each varix; tips of tubes delicate, glassy, more or less broken in all specimens; bases of tubes extended into a thick spiral ridge at the shoulder of the whorls. Suture distinct, impressed. Final varix forming a broad outer lip of nearly uniform width, obtusely angled at the base of the body whorl. Aperture subcircular, its protruding rim externally sculptured with strong growth lines and internally forming three blunt denticles within the palatal margin of old specimens (obscure or absent in younger shells). Anterior canal closed, straight, basally tapered, deflected to the right and abaperturally, long and terminally very delicate and therefore broken to some extent. Surface glossy, with faint, raised spiral lines on the body whorl below the shoulder; incised lines of growth distinct.Operculum broadly oval, with apical nucleus and strongly raised lamellar lines of growth. Radula not obtained.
Measurements. Holotype, Sta. P-718: length, 11.9 mm (anterior canal broken), width 6.2 mm.