The Siphonophora collected during the seasonal biological cruises of the R. V. 'Gascoyne' and R. V. 'Diamantina' during 1962-1963 have been studied in detail from samples taken from 227 stations with Indian Ocean Standard net by vertical haul (200-0 m) and Clarke Bumpus Sampler by oblique haul (0-200-0 m). 56 species are encountered in this region and their latitudinal and diurnal distribution pattern in the different seasons are presented.

Lensia panikkari Daniel previously recorded from Vityaz Stn. No. V. 5193 (Lat. 32°48/S & Long. 103''58/E) taken from 1000-0 m using an Ichthyological Net on 17-8-1962 has now been recorded at 'Diamantina' Stn. Dm 3/63 No. 95 (Lat. 24°30'S & Long. 1l0⁰'E) from a depth of 200-0 m during July - August 1962. Frillagalma vityazi Daniel, 1966, known from nectophores collected by the R. V. 'Vityaz' is now recorded from Dm 3/63 Stn. No. 97 (Lat. 21⁰30´S & 1l0⁰'E) together with bracts. Of the rest, 23 species are rare occurring only at one to ten stations; while nine species are very common occurring at more than 100 stations.