466 Thirty-fifth Report on the State Museum. 



CHARACTERS OF THE GENERA. 



CYATHOPHYCUS. 



" Hollow membraneous fronds with an opening at the upper ex- 

 tremity of the frond, elongate or hemispherical in form ; reticulate or 

 plain structure." 



DICTYOPHYTON. 



Turbinate, cylindrical or prismatic forms which may be infundi- 

 buliform above, consisting of a reticulate envelope, externally 

 marked by longitudinal and transverse striae which divide the surface 

 into minute rectangular spaces. Surface sometimes bullate or nodose 

 from the abrupt expansion of the envelope. 



ECTENODICTYA, 11. g. 



Discoid, globose, ovoid or irregularly expanding or explanate forms, 

 consisting of a reticulate frond or envelope. 



Several species referred to this genus are broadly spreading forms 

 which are flattened, discoid or subovoid in form, sometimes apparently 

 conforming to the sea-bottom and variously infolded or plicated. 

 The reticulation is irregular, presenting radiating and concentric 

 striae which are frequently interrupted and altered in their direction. 



LYRODICTYA, 71. g. 



Cyathiform fronds of a very fine reticulate tissue," composed of stel- 

 late spicules, with broad, strong, longitudinal bands of acicular 

 spicules showing an alternating bifurcation. 



THAMtfODICTYA, 11. g. 



Fronds tubular below, rapidly expanding and cyathiform or in- 

 fundibuliform above, with twelve strong longitudinal ridges dividing 

 the surface into twelve areas. Substance reticulate, as in Dictyophy- 

 ton. 



This genus was originally included among the typical forms of 

 Dictyophyton, but in the literature upon this subject the term has 

 generally been applied to such forms as D. tuberosum and D. Conradi, 

 and it would be unwise at the present time to restrict its application 

 as originally proposed. 



PHRAGMODICTYA, 11. g. 



Cylindrical or cup-shaped fronds, with a concave diaphragm near 

 the broadly expanded base. 



Substance composed of a reticulate tissue of six and three-radiate 

 spicules and long cylindrical rods. 



x 



