COCCONEIS. 29I 



are parasitic on Antithamnion cruciatum It corresponds to the var. crucifera 

 of Grunow (H.V.H. Atl , pi. 20, f. 20). It appears to me right to consider it 

 as the type form. 



var. Amygdalina (Cocc. diaphana W. Sm. parthn, S.B.D., 1., p. 22, 

 pi. 30, f. 254; H.V.H. Atl., pi. 30, f. 5 and 35*), plate 29, fig. 

 823 bis. 



Much larger in size, 3*5 to 4^5 c.d.m. Central nodule rounded, sur- 

 rounded by a small hyaline area. 



Marine. North Sea. England (Norman), Irelar.d (O'Meara), Jersey (W. Sm.). 



C. pseudo-marginata Greg. (Diat. of Clyde, p. 20, pi. 1, f. 27; 

 H.V.H. Atl., pi. 29, f. 20-21*), plate 2g, fig. 824. 



Valve broadly elliptic or suborbicular ; the upper showing a finely 

 striated pseudo-annulus, and on each side of the hyaline area a broad arcuate 

 sulcus; striae delicate, 20 to 24 in 1 c.d.m. on the portion exterior to the 

 sulcus, about 12 to 15 in the sulcus and the portion adjacent to the hyaline 

 area; lower valve without sulcus, finely striate, punctuate, about 13-15 striae in 

 1 c.d.m. Raphe robust, central and terminal nodules rather coarse, sur- 

 rounded by a small hyaline area. Length, 3-5 to 5 c.d.m. 



Marine. Scotland, Ireland, France. 



Group 7. MlCRONEis Cleve. Valve linear or lanceolate. 



Microneis delicatula (Kiitz.) Cleve is the Achnanthes {Achnanthidium 

 K'utz.) delicatula, which we have described in the last genus. 



