10 EUCRATIIDJi:. 



angles*; and not unfrequently these are not adherent, 

 but project as slender tubular processes. The fibre 

 generally is very loosely adherent, except on smooth flat 

 surfaces, where it is more closely adnate. 



There is very commonly a constriction just below the 

 aperture of the cell ; and at this point it is often broken 

 across. 



Family II. — Eucratiidae. 



ZocEciA uniserial, or in two series placed back to back, 

 expanding from the base upwards, iviih a terminal 

 or subterminal and usually oblique aperture. Avicu- 

 larian and vibracular appendages ivanting. Zoaria 

 forming slender, branching, phytoid tufts. 



This family group includes a number of forms of very 

 simjile structure and habit. The plan of the zoarium 

 exhibits no complexity and a very small amount of varia- 

 bility within its limits. The cells in a large proportion of 

 cases are linked together in single series, each rising from 

 the upper portion of the one below it. The erect shoots 

 thus formed give off branches ; and the pattern of the 

 ramification varies in the different genera. In the genus 

 Gemellaria we have a slight deviation from the perfect 

 simplicity of habit which is so characteristic of this family. 

 The Eucratea-\\ke cells are here disposed in a double 

 series, and adhere to one another by the dorsal surface, so 

 that the apertures of the two rows look in opposite direc- 



* I have seen a luxuriantly developed specimen on weed, in which these 

 lateral branches were present in profusion, attaining a considerable length 

 and bearing lines of cells. They wei*e slender and of uniform thickness 

 throughout, and showed no trace of the usual enlargements. 



