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 Labechia originally placed by Edwards and Haime 

 among the Chcetetidce 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 Ctuetetida proper; while such resem- 

 blances as it shows to certain of the Monticuliporida are 

 largely counterbalanced by special and apparently inexplicable 

 peculiarities of its own. 



