Studies on Indian Echinoderms 2. The holothurian Stolus buccalis (Stimpson) with notes on its systematic position

While collecting echinoderms in the Palk Bay and Gulf of Mannar the author found five specimens of holothurians, two at Rameswaram (9° 17' N., 79" 22' E.) and three at Mandapam (9° 15' N., 79° 09' E.), which should be referred to Stolus buccalis (Stimpson) (PI. I). This species has been reported earlier from the Indian region by Gravely (1927, 1941) under the name Thyone sacellus but since this name no longer holds good and since no adequate description is available it is felt necessary to describe the specimens collected