ZOOLOGY OF THE BERMUDAS. 129 



The outer portion of the mesoglcea for about half its thickness 

 has imbedded in it foreign bodies, and when decalcified is 

 fenestrated by the numerous cavities previously occupied by 

 them. The internal portion of the layer presents the structural 

 features found in other Zoanthidse, but it is to be noticed that 

 foreign bodies occur in the so-called " nutritive canals " or 

 lacunae. The sphincter muscle is imbedded in the mesogloea, 

 is single, and consists of a single row of cavities containing 

 muscle fibres. 



The tentacles are arranged in two rows, and are apparently 

 fifty-six in number in the specimens examined. Their outer 

 muscular layer is weak, and the mesogloea is homogeneous, ex- 

 cept upon the outer face of the tentacles, where it contains a 

 number of granular cells similar to those occurring in the 

 column mesoglcea in this and other forms already described. 

 Zooxanthellse occur in the ectoderm. 



The ectoderm of the disc is peculiar! It consists of high, 

 much-vacuolated cells which contain, like the ectoderm of the 

 tentacles, zooxanthellse. I have found this peculiar structure 

 of the disc ectoderm in no other Zoanthids. Unfortunately 

 the preservation of the specimens was not sufficiently good to 

 allow of the histological details being studied. The gonidial 

 groove of the stomatodseum is rather broad, and the mesogloea 

 lining is thickened and truncated upon the endoderrnal side, 

 the macrodirectives being inserted into each angle of the 

 truncation. 



The mesenteries are arranged on the microtypus, there 

 being about twenty-six pairs. The basal canal is large, and 

 contains foreign particles similar to those found in the lacunae 

 of the column. The mesoglcea is thickened towards the base 

 of the mesenteries and contains, in addition to the basal canal, 

 several others nearly circular in section and completely filled 

 with spherical granular cells. The endoderm throughout con- 

 tains zooxanthellse. No reproductive organs were present. 



Cortioifera glareola, Les. 



Corticifera glareola. Lesueur. 1817. 

 Palythoa glareola. Milne-Edwards. 1857. 



