ZOOLOGY OF THE BERMUDAS. 133 



each tentacle of the outer cycle. The elevations are produced 

 hy thickenings of the mesogloea (PL 11, fig. 9), and along each 

 ridge the ectodermal muscle cells are more numerous and 

 larger than elsewhere. G. isolata presents similar structures. 

 Zooxanthelloe occur in the ectoderm of the disc, and tentacles 

 in both forms. The enclosures in the mesogloea of the disc, 

 which I thought might possibly be muscle cells in G. isolata, are 

 seen in G. Rusei to be comparable to the lacunae of the column 

 wall. 



The mesogloea of the stomatodreum in both species of Gem- 

 maria has enclosures of granular cells (PL 11, fig. 8), as a 

 rule one such enclosure opposite the insertion of each mesen- 

 tery, especially in the upper part of the stomatodaeum, the ar- 

 rangement being lost in the lower part. The gonidial groove 

 has the same shape as that of G. isolata. 



The mesenteries are arranged in thirty-one pairs and are on 

 the microtypus. The mesogloea thickens towards the base so 

 that the basal canal is almost circular and not elongated as in 

 G. isolata. No reproductive organs were present. 



The description given by Duchassaing and Michelotti of 

 Gemmaria Rusei, with which I identify this form, is very im- 

 perfect, but so far as it goes it applies to the Bermuda species. 

 The form described by Gray* as Triga Philippinensis is very 

 similar in external form and is in all probability a Gemmaria. 



Of the forms described above, no less than seven, viz: Con- 

 dylactis passiflora, Phymanihus cruci/er, Zoanthus flos-marinus, 

 Mammillifera turberculata, Corticifera ocellata, C. glareola and 

 Gemmaria Rusei, are represented in the West Indian fauna, and 

 of the other three, the genera Aiptasia and Phyllactis also 

 occur in the islands to the South, leaving only the genus 

 Diplactis as a characteristic form of the Bermudas. No doubt 

 a systematic search for actinians in the Bermudas would lead 

 to the discovery of a greater number of West Indian forms, 

 but the proportion of common forms given above is sufficient 



* J. E. Gray. Notes on Zoantliinse with Descriptions of some New Genera. Proc. 

 Zool. Soc. London r .1867. 



