211 
The contents of the sheath (fig. 2) are so closely convoluted that it 
is difficult to make out if they consist of one long thread or tubule or of 
an enormous number of short threads. Stained with iron haematoxylin 
and seen in a great mass they would appear to be spermatozoa, for a 
dark portion of the thread, surmounting a less staining prolongation is 
easy to make out; but when the threads are seen separately they seem 
to form a continuous cord dotted by darkly staming bands at more or 
less regular intervals apart (about 1 «). The spermatozoa, when they 
occur loose in the zooecium have a very discernible spear-shaped head 
and average about 11/2 u in length, whereas the threads in the long body 
are only surmounted by a dot. The enveloping membrane of the organ 
seems to be closed completely, but the cells which compose it are 
usually larger and more marked at one end or the other. 
In zooecia in which spermatic tissue occurs this body lies right in 
the testicular stroma; spermatozoa may be detected fastened in large 
numbers to it although it still appears to be closed. In zooecia which 
have formed a root process the body seems to make its way through the 
root aperture; it is largest and most conspicuous in zooecia which con- 
tain a brown body, whether there is a growing bud present or not. 
Although the most usual shape is that of a more or less even cylinder 
it may often be found with constrictions along its length giving it more 
the appearance of a string of sausages. 
Waters (6) describes an unpaired «sausage body» in Schixo- 
porella sanguinea, also containing unstaining patches. Fixed and 
stained in the same way as in the Flustra it shows a rather similar 
structure. The clear spaces seem like crystals, but tested by polarized 
light they prove not to be; the contents consist of threads so short that 
in thick section they appear to be granules, there is no possibility in this 
case of a single continuous tubule. A body of an allied nature occurs 
in Beania magellanica (Busk) and in Beania hirsuta, var. cylindrica 
(Hincks). Waters draws attention to the existence of a long body of 
unknown function in Scrupocellaridae (9) and (8) in Bugula bicornis 
(Busk); these may be homologous with the long body in Flustra papyrea. 
Whether this body is in truth a form of spermatophore, or, suppos- 
ing it is a coiled tubule, what purpose it can serve, seems hard to 
understand. Jullien (3) and Waters (6) have hazarded the suggestion 
that there may be a double method of reproduction in the Cheilosto- 
mata as in the Phylactolaemata and that these organs may represent 
seasonal eggs; but the structure of the flustrine long body, the absence 
of any means of exit from the zooecium, its presence after the death of 
the polypide and the fact that it is to be found unfailingly in some part of 
the colony at all times of the year all tend to render the hypothesis unlikely. 
14* 
