Polypide. The polypide is comparatively short and stout. European specimens are said to have from 30 to 40 tentacles, but Indian specimens have only from 20 to 30.
Shrunken specimens of the less congested forms of this species closely resemble specimens of P. repens, but the statoblasts are more variable in shape and the ectocyst, even in such specimens, is thicker. Living or well-preserved specimens cannot be mistaken for those of any other species. Jullien regarded P. punctata as the type of a distinct genus (Hyalinella) but included in Plumatella at least one form (P. "arethusa") which probably belongs to this species. Kraepelin distinguishes as "varieties" two phases, a summer phase ("var. prostrata") and an autumn phase ("var. densa"). The former often forms linear series of considerable length with only an occasional side-branch, while in the autumn phase branching is so profuse and the branches are so closely pressed together that the zoarium comes to resemble a uniform gelatinous patch rather than a dendritic growth. A phase resembling the European autumn form is the commonest in Calcutta and I have also found one intermediate between this and Kraepelin's "var. prostrata," neither having any seasonal significance in India.
Geographical Distribution.—P. punctata is widely distributed in Europe and N. America, but in the Oriental Region it has only been found in Calcutta and the neighbourhood.
Biology.—In this part of India P. punctata flourishes both during the "rains" and in winter. I have found specimens in June and July and also in December and January. The majority of them were attached to bricks, but some were on the roots of duckweed, the stems of water-plants, and the tips of creepers falling into water. The species is often found together with Stolella indica and also with other species of its own genus. It is most common, in the neighbourhood of Calcutta, in that part of the town which is near the Salt Lakes, and occurs in ponds the water of which is slightly brackish.
Genus 2. STOLELLA, Annandale.
Stolella, Annandale, Rec. Ind. Mus. iii, p. 279 (1909). Stolella, id., ibid. v, p. 53 (1910).
Type, Stolella indica, Annandale.
Zoarium. The zoarium consists of groups of zoœcia (or occasionally of single zoœcia) joined together by an adherent rhizome. There is no gelatinous investment.
Zoœcia. The adult zoœcia resemble those of Plumatella except in being sometimes more or less upright.
Polypide and Statoblasts. The polypide and statoblasts resemble those of Plumatella. Fixed as well as free statoblasts occur.