!44 



BREBISSONIA. 



GENUS 16. BREBISSONIA GRUN., i860. 



Valve with central nodule linear, very 

 elongate ; terminal nodules distant from apices. 

 Frustules pediculate. 



Brebissonia Boeckii (Kutz.) Grun. 



(i860, Wien, p. 512 ; Doryphora Boeckii, IV. Sm., 

 S.B.D. i., p. 77, pi. 24, f. 223; H.V.H., Type No. 



150)- 



Fig. 44. Brebissonia 

 Boeckii. 



GENUS 17. 



Valve lanceolate, rhomboidal, with striae very 

 robust, radiate, 10 in 1 c.d.m., finely divided 

 transversely like those of the Radiosce (Navicula). 

 Raphe surrounded by a considerable hyaline area, 

 often narrowed near the central nodule, slightly 

 extended beyond the terminal nodules. Length, 7 

 to 13 c.d.m. Breadth at the median portion, 2 

 c.d.m. 



Marine. England (W. Sm., Kitton, Norman); Dundee, Scot- 

 land (Kitton in Baxter's Coll., No. 3463); Ireland (O'M.); Kiel, 

 Germany (Eulenstein) ; North Sea, near Christiania (D. Boeck). 



ROUXIA J, BRUN AND F. HERIBAUD, 



1893. 



Valve elongated, linear, with central nodule 

 rudimentary or absent, terminal nodules very 

 elongated, and narrow at the apices. A row of 

 beads round the nodules and the raphe, which is 

 not distinct. Frustule 

 A single exotic species. 



girdle view sigmoid. 



Fig. 45. Rouxia 

 Per agaili. 



Rouxia Peragalli J. Brun and F. Herib. 

 (Diat. d'Auvergne, p. 156, pi. 1, f. 12). 



From Japan. 



The authors of the genus place it among the 

 Pseudo-raphidieae, but as it appears to me to have a 

 greater affinity to the Amphiphura, Berkdeya etc., 

 I prefer to arrange it near those genera. 



