GUINARDIA. 



4^7 



GENUS 86. GUINARDIA, H. Per., 1892. 



Frustules cylindrical, annulate ; valves 

 circular, showing an undulation ending in an 

 elementary mucro. 



Fig. 135- 

 Guinardia flaccida. 



G. flaccida (Castr.) H. Perag. (Monogr. Rhizos., p. 107, pi. 



h l 3-5)- 



Frustules cylindrical, valves hyaline, furnished with a small projecting 

 spur, lateral, placed on the summit of an undulation of the valve ; rings flat, 

 hyaline, imbricated in twos ; lines of imbrication oblique, simple and opposite. 

 Diameter, 25 to 80 c.d.m. Silica very slight, frustule completely put out of 

 shape by dessication (H.P.). 



Marine. Maritime Scheldt (H.V.H.), Kattegat (Cleve). Peragallo says it is very wide-spread. 



D D 



