HOWE 



PLATE 2 



Lithothamnium concretum, n. sp. 



Fig 1 —Photograph of radio-vertical section (from same specimen as fig- 2), showing '-■ell struc- 

 ture, tetrasporic conceptacles, etc., enlarged 100 diameters. The surface of the thallus 

 is toward the light. . . , 



FlG . 2.— Photograph of radio-vertical section, showing zonations, tetrasporic conceptacles, etc., 



