AMPHORA. 127 



A. OValis Kutz. (Bac. p. 107, pi. 5, fig. 35 and 39; H.V.H. Ati., 

 pi. 1 f. 1* Type No. 1) plate 1, fig. 15. 



Frustule oval, very inflated at the median portion, then slightly atten- 

 uate ; apices broadly truncate. Valves arcuate at dorsal margin, concave 

 at internal margin ; raphe inflexed ; striae strongly marked with coarse puncta 

 from 10 to n in 1 c.d.m. without stauroneiform blank space. Length, 



5 to 7 c.d.m. 

 Fresh water. Common everywhere. 



/3 gracilis (A. gracilis E. Verb. p. 122, n. 11, pi. III. 1, f. 43 

 H.V.H. Atl., pi. i,' f. 3*) plate 1, fig. 16. 



Considerably narrower and more slender in all parts than the pre- 

 ceding ; apices rounded, subacute ; raphe very inflexed. 



Mixed with the preceding. Louvain. 



y. affinis Kutz. (Bac, p. 107, pi. 30, f. 66 ; A. abbreviaia Blrisch ; 

 H.V.H. Atl., pi. 1, f. 2*; Type No. 2) plate 1, fig. 17. 



Frustule oval, with apices slightly tapering ; striae rather finer (about 

 12 in 1 c.d.m.) leaving a stauro-form blank space very distinct 

 on the dorsal side. Length, 3 c.d.m. 



Fresh and slightly brackish water. Blankenberghe(pure gathering). Louvain (H.V.H.) 

 Ardenne Liegeoise (De Wild). Free or mixed with the preceding. England (Norman, 

 W. Sm.). 



forma minor (A. Pediculus major Grun ; H.V.H. Atl., pi. 1, 

 f. 4, 5*) plate 1, fig. 18. 



Smaller, about 3 c.d 111. in length; striae fine, about 16 in - oi 

 c.d.m. 



Louvain, etc. 



8. Pediculus Kutz. (A. Pediculus (Kiitz.) Grun. Cymbella 

 Pediculus Kutz. Bac, p. 80, pi. 5, f. VIIL, and pi. 6, f. VII. A. 

 minutissima, IV. Sui., S.B.D. i., p. 20, pi. II., t. 30. H.V.H. Atl, 

 pi. 1, f. 6, 7*; Type No. 3) plate 1, fig. 19. 



Frustule small, with apices slightly narrowed; pseudo-stauros very 

 distinct; raphe more or less concave; striae 16 in 1 c.d.m.; length 

 about 2 c.d.m. 



Generally parasitic on other diatoms, and especially on Nitzschia Sigmoidea. 

 Common. Antwerp, Louvain, Blankenberghe (H.V.H. ) Aid. Lig. (De Wild.), 

 etc. England (W. Sm., Norman, Stolterfoth). 



forma minor, Grun. (H.V.H. Atl., pi. 1, f. 8*), plate 1, 

 fig. 20. 



Still smaller, about 1*5 c.d.m. in length ; about 20 striae in 

 1 c.d.m. 



forma exilis, Grun. (H.V.H. Atl., pi. 1, f. 9, 10*), plate 1, fig. 



21. Small, very narrow, length from 1*5 c.d.m., striae about 20 in 1 



c.d.m. 



A. perpusilla Grun (h.v.h. Atl., pi. i, f. n*; Type, No. 4), 

 plate 1, fig. 12. 



