The present paper was communicated with the taxonomic description and ecology of two species of the genus Volvox L. viz. Volvox aureus Ehr. and Volvox globator L. under the order Volvocales of class Chlorophyceae. They are freshwater and planktonic phycoflora. The colony of former species was comparatively smaller (340 µm) than the later (480 µm) whereas, somatic cells were found slightly larger in the former species in comparison to later species. Both were colonial, multicellular, greenish and formed dots like appearances in the water bodies and, exhibited phototactic movements. These two species were being reported first time from Hooghly of West Bengal, India. The ecological study showed that they preferred to grow in alkaline water (pH 7.3-7.5) with slight high organic nutrient contents (NO3-N: PO43- ratios: 0.25-0.35: 0.30-0.32 mg/l). This study also revealed that higher total alkalinity values (174.0-184.0 mg/l) were favorable for their developments and their maximum growth noticed in summer in aquatic ecosystems.
