ZOOLOGY OF THE BERMUDAS. 133 



each tentacle of the outer cycle. The elevations are produced 

 by tliickenings 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. 

 Zooxanthella^ 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. Bttsei to be comparable to the lacunse of the column 

 wall. 



The mesogloea of the stomatoda^um in both species of Gem- 

 nmria has enclosures of granular cells (PI. 11, fig. 8), as a 

 rule one such enclosure opposite the insertion of each mesen- 

 tery, especially in the upper part of the stomatodasum, 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 hj Duchassaing and Michelotti of 

 Gcmmaria Eusei, 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 Tric/a Philippinensis is very 

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



Of the forms described above, no less than seven, viz: Co7i- 

 dyladis passiflora, Phymanth^is crucifn; Zoanthus flos-viariiius, 

 Mammillifera turbarulafa, Corficifera ocellata, C. glareola and 

 Ge))nnaria Rusei, are represented in the West Indian fauna, and 

 of the other three, the genera Aiptasia and Phylladis also 

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

 Dipladis as a characteristic form of tlie Bermudas. No doubt 

 a systematic search for aetinians in the Bermudas would lead 

 to the disco ver3' of a greater number of West Indian forms, 

 but the proportion of common forms given above is sufficient 



* J. E. Gray. Notes on Zoantliin^e wuU Descriptions of some New Genera. Proc. 

 Zool. Soc. London, 18G7. 



