STRIATELI.A. 363 



S. delicatula (Kutz.) Grun. (Hyalosira delicaiula Xutz.,Bac, 



pi. 18, f. 3 (1), etc. j H.V.H. Atl., pi. 54, f. 5 and 6*; Type No. 357), plate 

 12, fig. 483,7. 



Valve elliptic lanceolate ; striae very fine, 36 in 1 c.d.m. Girdle face 

 quadrangular, showing 4 to 5 pairs of septa, alternate, robust at the margin 

 of the frustule, but becoming gradually slender. Length, about 1 c.d.m. ; 

 breadth, up to 1*5 c.d.m. 



Marine. Ostend (Westendorp in No. 797). Heligoland (Kutz.), and probably on all the 

 coasts of the North Sea, where it is overlooked in consequence of its small size and delicate 

 nature. 



S. interrupta (Ehr.) Heiberg. (Danske Diat, pi. 5, f. 15; 



H.V.H. Atl., pi. 54, f. 8* ; Type No. 358 ; Te'ssella interrupta Ehr.), plate 

 12, fig. 484^. 



Valve linear elliptic, with pseudo-raphe very distinct ; girdle face quad- 

 rangular, with rounded angles, showing numerous false septa, alternate, clearly 

 visible up to the middle of the length of the frustule, with intervals covered 

 with delicate granules (22 in 1 c.d.m.) arranged in quincunx, and producing 

 with oblique illumination the image of very approximate fine stria?. Length, 

 about 3 c.d.m. Breadth, about 6 c.d.m. 



Marine. Not yet found in Belgium. Flessingue (H.V.H.), England, Ireland, Germany, 

 Heligoland, Bahnsie. 



S. unipunctata Agardh. (Kutz. Bac, pi, 18, f. 5 ; h.v.h. Atl., 



pi. 54, f. 9 and 10* ; Type No. 359), plate 12, fig. 485,7. 



Vaive broadly lanceolate, with pseudo-raphe very distinct, covered with 

 very fine puncta, arranged in curved lines ; girdle face showing very numerous 

 septa, extending throughout the length of the frustule, with intervals filled 

 with fine puncta (more marked on the margin of the false septa), arranged in 

 lines cutting one another at right angles, about 23 in 1 c.d.m. With oblique 

 illumination these rows of beads assume the appearance of lines as in 

 fig. 485 (right hand fig.). Figure 485 (left hand fig.) represents the appearance 

 of lines which the rows of beads on the valve can assume. Length, about 6 

 to 8 c.d.m. Breadth, more than 10 c.d.m. 



Marine. Not yet found in Belgium. Coasts of the North Sea: England (Kitton, Comber, 

 Stolt), Ireland (W. Sm., O'Meara), France, Heligoland, Denmark, Bahnsie. 



