CLASSIFICATION. 29 



which are close -set tubercles. Microscopic sections show 

 that these tubercles are the projecting summits of a series 

 of short, calcareous, and entirely solid, though seemingly 

 primitively tubular, columns, separated from one another by a 

 loose vesicular tissue, formed by the anastomosis of curved 

 calcareous lamellae. Dr Lindstrom has strongly supported the 

 view that Labcchia — originally placed by Edwards and Haime 

 among the ChcstetidcB — is truly a Hydrozoon, allied to Hydrac- 

 tinia. The peculiarities in its structure are, however, so 

 numerous, and the apparent total absence of any superficial 

 openings of any kind is so puzzling, that I do not at present 

 see how it can be placed among either the Hydrozoa or the 

 Actinozoa ; nor am I able to give any definite opinion as to 

 its affinities beyond the negative one, that it certainly has no 

 relationships with the ChcctetidcB proper; while such resem- 

 blances as it shows to certain of the Monticulipo7'-idcB are 

 largely counterbalanced by special and apparently inexplicable 

 peculiarities of its own. 



