FRAGILARIA. 325 



var. prolongata Grun. (H.V.H. Atl., pi. 40, f. 10* ; Type No. 319), 

 plate 11, fig. 445. 



Valve very narrow, with apices not capitate. Length, about 10 c.d.m. 



Fresh water. Botanical Gardens, Brussels (Del.). 



II. STAUROSIRA. Pseudo-raphe broad, often more or less 



lanceolate. 



F. capucina Desmazieres (Piantas Crypt. Ed. I. (1825), No. 

 453 ; H.V.H. Atl., pi. 45, f. 2*), plate 11, fig. 446. 



Valves linear, narrow, with apices somewhat produced rostrate. Margin 

 of valve marked with very distinct coarse beads, continued towards the 

 internal portion by delicate stride, 14 or 15 in 1 c.d.m. Frustules united into 

 long filaments. Length, 3 to 6 c.d.m. 



Fresh water. Common everywhere. 



var. mesolepta (F. mesolepta Rab. ; H.V.H. Atl., pi. 45, f. 3* ; 

 Type No. 312), plate 11, fig. 447. 



Valve strongly constricted at the median portion, with apices rostrate 

 and sometimes capitate ; striae 17 or 18 in 1 c.d.m. 



Fresh water. Rather common. 



var. acuta Grun. (H.V.H. Atl., pi. 45, f. 4*), plate 11, fig. 448. 

 Valve narrowly lanceolate with sub-acute apices. 



var. acuminata Grun. (H.V.H. Atl., pi. 45, f. 8*), plate 11, fig. 

 449- 



Valve narrowly lanceolate, with apices longly and narrowly rostrate ; 

 stria? 18 in 1 c.d.m., delicate. 



Fresh water. Paliseul (Delogne). 



F. construens (Ehr.) Grun. ! (Oestr. Diat., p. 371; h.v.h. 



Atl., pi. 45, f. 26, E and D figures on the right and left, and f. 27*) ; in Type 

 No. 190), plate 11, fig. 450. 



Valve broadly oval, constricted somewhat below the median portion into 

 rostrate-capitate apices, giving a cruciform appearance. Pseudo-raphe lanceo- 

 late. Strise fine, about 15 in 1 c.d.m. Length, about 1*5 c.d.m. 



Freshwater. Somewhat rare; England (Kitton), Ireland (O'Meara) ; found throughout 

 Europe. 



var. Venter. (H.V.H. Atl., pi. 45, f. 21B, 22, 23, 24B, and- 26 

 (upper and lower * figures) ; in Type No. 190), plate 11, fig. 451. 



Valve lanceolate, with obtuse apices, inflated at the median portion. 



Freshwater. Brussels (Delogne). Sheene Dep. Aberdeen (Temp, and Perag., No. 



443)- 



