Polyzoa Kntoprocta and Ctenostomata. 25 
1911. Bowerbankia caiidata su1)sp. bengalensis, id., Faun. Brit. Ind., FrcsJvw. Sponges, etc., 
p. 189. 
1915. Bowerbankia caudata, id., Mem. Ind. Mus. V, p. 126. 
I have already discussed this form so often that it may seem superfluous to return 
to it again, but it is clear from Harmer's remarks in his report on the ' Siboga ' Polyzoa 
that a detailed description ia still called for on my part. Harmer refers to my figure 
of the zooecium, but I never published one. 
In the form I call Bowerbankia caudata the colony consists of zooecia arising 
singly, in pairs or in groups on both sides of a reptant rhizome that branches more or 
less freely both in a cruciform and in a dichotomous manner. The rhizome may 
occasionally be free for a considerable part of its length, but is usually adherent and 
Fig. 4. — Bowerbankia caudata. 
A. — Two polypides with apparently bifid bases, x 45. B. — Lower part of two other polypides in 
one of which the base has become attached to a fragment of stone, x 45. C. — Fully expanded poly- 
pide, X45. 
c. = collar, ca. = oesophageal valve. /. = funiculus. (>. = gizzard, i. = intestine, o. = orifice of zooecium. oe. = 
oesophagus, p. = pharynx, pr. = proveutriculus. r. = rectum, s. = stomach. 
never gives rise to upright branches. The zooecia are invariably attached to the side 
of the rhizome, with the interior of which they communicate by means of a circular or 
oval aperture of relatively large size in their own wall and in that of the rhizome. Ver- 
tical partitions, each perforated by a single pore, occur at intervals in the rhizome. In 
the younger parts of the colony the normal arrangement seems to be that two zooecia 
arise approximately opposite one another; a partition occurs in the rhizome close to 
the pair of zooecia in the direction nearest to the centre of the colony, and another at 
some distance away, near another pair of zooecia, in the opposite direction; but this 
arrangement is liable to all kinds of irregularities and practically disappears in con- 
gested parts of the colony, where, for considerable distances, the zooecia are closely 
packed together on one or both sides of the rhizome and partitions are absent or scat- 
tered irregularly. There is never any trace of a spiral arrangement of the zooecia. 
