[Footnote BN: It is now perhaps open to doubt whether the investment is actually secreted by the polyzoon, for Prof. W. West has discovered in it the cells of an alga belonging to a genus which habitually secretes a gelatinous investment of its own (see p. 238, _post._).--_April 1911._] The type-species was originally found in N. America but has since been taken in several localities in continental Europe. Except this and the Indian form only one species is known, namely _P. gelatinosa_ from Japan. _P. magnifica_ has circular statoblasts with long marginal processes, while in _P. gelatinosa_ the statoblasts are subquadrate and in _P. burmanica_ almost circular, both Asiatic forms having very short marginal processes. The compound colonies formed by _Pectinatella_ are often of great size. Those of _P. gelatinosa_ are sometimes over 2 metres in length, while those of _P. burmanica_ in the Sur Lake appeared to be only limited as regards their growth by the shallowness of the water in which the reeds to which they were attached were growing. Some were observed that were over 2 feet long. 38. Pectinatella burmanica, _Annandale_. (Plate III, fig. 5.) _Pectinatella burmanica_, Annandale, Rec. Ind. Mus. ii, p. 174, fig. 5 (1908). _Pectinatella burmanica_, _id._, _ibid._ v, p. 56 (1910). _Pectinatella burmanica_, _id._, Spol. Zeyl. vii, p. 63, pl. i, fig. 3 (1910). _Zoarium._ The zoaria are circular or nearly so except when about to undergo division, in which case they are constricted in the middle. As a rule they measure nearly an inch (2 cm.) in diameter. The polypides have a definite arrangement in each zoarium, being divided into four groups, each of which has a fan-like form. In the first place they are separated into two main divisions in a line running through the centre of the zoarium, and secondly each main division is separated into two subordinate ones in a line running across the other at right angles. The number of zoaria joined together in a single compound colony is very variable; sometimes there are only about half a dozen and sometimes several hundreds. The common investment in living colonies is often as much as two inches thick and has a translucent dark greenish colour due to the presence in it of green cells. [Illustration: Fig. 47.--_Pectinatella burmanica._ A=polypide with the lophophore expanded, × 15; _a_=oesophagus; _b_=cardiac limb of stomach; _c_=stomach; _d_=rectum; _e_=anus; _f_=funiculus. [The muscles are omitted and the external tubercles are only shown on part of the polypide. The specimen is from the Sur Lake, Orissa.] B=statoblast from Ceylon, × 35.] _Polypide._ The polypide can be extruded for a distance of at least 5 mm. Its whole external surface is covered with minute tubercles. There are about 90 tentacles, which are long and slender, the velum at their base being narrow and almost straight. The stomach is of considerable stoutness.