No. 6.] THE MORPHOLOGY OF THE ACTINOZOA. 255 



In the Zoantheae the ciliated bands are, as a rule, the most 

 striking portions of the filaments, and, consequently, have 

 received more attention than the glandular streaks. The 

 earliest writer on the filaments of the Zoantheae, Lesueur 

 ('17), describes, however, both portions in ZoantJms solanderi 

 and in Palythoa {Corticifcra) glarcola. He described white 

 filaments bordering the edges of the mesenteries and noted that 

 above, attached to the base of the stomach, there were " thick 

 white arcuated organs, striated 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 called them, the 

 arcuated organs, might "be considered as performing the func- 

 tions of the liver." 



Dana ('46) described the glandular streaks in P. cacsia 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 branchiae, 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 nor Verrill 

 perceive their identity with the ciliated bands of the Hexactiniae 

 which had been described by Haime and Thorell. This was 

 left for R. Hertwig ('82), who described them as portions of the 

 mesenterial filaments of his Z. danae (?) and pointed out that it 

 is quite erroneous to consider them as structures peculiar to the 

 Zoantheae. 



Erdmann ('85) described both the glandular streaks and the 

 ciliated bands, adding, however, nothing to our knowledge of 

 their structure ; and Koch ('86) failed to find mesenterial fila- 

 ments in the forms which he studied, and maintained that they 

 were not present, at least in the same form as in other actin- 

 ians. Three years later I described ('89) the two portions of 

 the filaments of Z. flos-mariiiiLS, and, in addition, noted that 

 the cells covering the surfaces of the mesenteries for some 

 distance outwards from the glandular portions of the filaments 

 were much higher than the general endoderm, and were loaded 



