390 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. VI. 
that the central lobes of the ciliated bands is in reality the upper part- 
of the glandular streak. 
The arrangement just described may be regarded as the typical one 
for the Hexactinian filaments, though certain departures from it have 
been observed. Thus, in the Madreporaria the ciliated bands have not 
yet been observed, and they are also absent in certain Actiniaria, such 
as Protanthea and Gonactinia (Carlgren, 1893), and Corynactis, Ricordea 
and Rhodactzs (Duerden, 1898).* So far, however, as the majority of 
the Hexactiniz are concerned, both parts occur. 
In the Zoanthee the ciliated bands are, as a rule, the most striking 
portion of the filaments, and, consequently, have received more attention 
than the glandular streaks. The earliest writer on the filaments of the 
Zoanthee, Lesueur (1817) describes, however, both portions in Zoanthus 
Solandert, and in Palythoa (Corticifera) glareola. He described white 
filaments bordering the edges of the mesenteries, and noted that above, 
attached to the base of the stomach, there were “thick arcuated organs, 
situated in annulations, folded on each other, and divided through their 
whole length by a small “canal.” He thought that the ciliated bands, 
or, as he termed them, the arcuated organs, might “be considered as 
performing the functions of the liver.” 
Dana (1846) described the glandular streaks in P. cwsza as spermatic 
cords, and noted that “above the spermatic cords there is attached to 
each larger lamella, immediately below the stomach, a pair of flat 
branchia-like organs.” Verrill, who observed these same structures in 
1869, agreed with Dana in regarding them as branchie, and they were 
again briefly described by Andres in 1877. None of these authors, 
however, seemed to regard the “ branchia-like” or “arcuated” organs 
as parts of the mesenterial filaments, nor did Andres or Verrill perceive 
their identity with the ciliated bands of the Hexactiniz which had been 
described by Haime and Thorell. This was left for R. Hertwig (1882), 
who described them as portions of the mesenterial filaments of his 
Zoanthus Dane (?), and pointed out that it is quite erroneous to con- 
sider them as structures peculiar to the Zoanthee. 
Erdmann (1885) described both the glandular streaks and the ciliated 
bands, addng, however, nothing to our knowledge of their structure ; 
and Koch (1886) failed to find mesenterial filaments in the forms which 
he studied, and maintained that they were not present, at least in the 
same form as in other Actinians. 
*] may state that I can confirm Duerden’s observations as to the absence of the ciliated bands in the 
last two forms. 
Me ee ee 
me 
