132 E. GROVE AND G. STURT ON 



by the presence of two nodules, situated on the longitudinal 

 axis of the valve, midway between the centre and extremities. 

 Longest diameter about -001 5". Rare. (PI. X, Fig. 5.) 



Navicula inelegans, n. sp., Gr. and St. — Valve in frustular 

 view very convex, in outline spindle shaped, usually with an 

 enlarged centre, but very variable in this respect. Stria? sub- 

 radial, about 37 in '001", reaching the central line. Owing to 

 the convexity of the ends, the terminal nodules are not seen in 

 the valvular view as is the case in Stauroneis acuta, W. Sm. 

 (This form may be filamentous, and if so should belong to 

 Diadesmis.) Length of specimen figured about '0057". Not 

 rare. (PI. X, Fig. G.) 



N. margin o-punctata, n. sp., Gr. and St. — Valve resembles 

 in outline N. jamaicensis, Grev. (" T. M. S.," Vol. xiv, p. 126, 

 PI. 12, Fig. 23), but differs entirely in other respects. On 

 each side of the central line the valve is quite devoid of mark- 

 ings, but at the extreme margin are two rows of granules. 

 Pare. Length -0048". (PI. X, Fig. 7.) 



N, trilineata, n. sp., Gr. and St. — Oval, median line and 

 nodules distinct. Striae costate, parallel, divided by clear 

 longitudinal spaces into three distinct groups on each side. 

 Length -004" ; breadth -0013". Rare. (PL X, Fig. 8). 



N. biconstricta, n. sp., Gr. and St. — Valve trinodular, the end 

 lobes being slightly broader than the central inflation. Median 

 line and nodules conspicuous. Margin cellulate with short costa3 

 about 20 in *00 1", not reaching to the centre line. Length -0035" ; 

 breadth of end lobes -00065". (PI. X, Fig. 9.) 



N. dispersa, n. sp., Gr. and St. — Valve lanceolate, with 

 subacute ends. Median line distinct. Striae obscure (about 55 

 in "00 1"), reaching to the centre line, excepting at the centre of 

 the valve, where there is a clear oval space. As the striae 

 approach the margin they break up into scattered dots, leaving 

 a submarginal clear space, which is broader towards the ends 

 than at the centre of the valve. On the margin is a closely 

 set row of small puncta. Length -0047". (PI. X, Fig. 10.) 



JV. margino-lineata, n. sp., Gr. and St. — Valve small, slightly 

 constricted, with an outline resembling that of N. didyma, Ehr. 

 Median line and end nodules distinct. Central nodule slightly 

 dilated. Margin edged with a closely set line of puncta, within 

 which, separated by a narrow clear line, is a row of very short 



