72 



p. T. CLKVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



To this genus probably belongs Stauroneis decora GtEEV. (T. Bot. Soc. of Edinb. Vol. VIII 

 p. 236 PL III f. 11) from New Caledonia. It is very transparent, lanceolate, in length 0,i4 mm. 

 and has a short stauros not reaching the longitudinal ridges. 



Scoliotropis Cl. N. G. 



Valve elongated symmetrical. Median line slightly sigmoid, especially towards the ends. 

 On both sides of the median line is a longitudinal line. Structure double : coarser transverse costse 

 and finer puncta, disposed in obliquely decussating rows. Connecting zone with longitudinal rows 

 of short striee. 



This genus has been formed for ScoUopleura latestriata Grun. as this form is entirely 

 diiferent from the true Scoliopleura-forms in its structure, which is the same as in Gomphoneis, 

 and in the complex nature of its connecting zone. Later on another, very interesting species, 

 was discovered, unfortunately not yet found in entire specimens, S. GiUesii. 



The frustules of S. latestriata have along the connecting zone 

 on each side, two chromatophore-plates, the margins of which are 

 gently undulating. In front-view the plates have a sinus around 

 the centra] plasma-mass. 



1. S. latestriata Bk^b. (1849). — V. linear, narrowed at the 

 cuneate ends. L. 0,i to 0,i8; B. 0,o2.'i mm. Median line strongly 

 sigmoid. Structure: strong costse, 7 in 0,oi mm., transverse, trough- 

 out, and minute puncta, 18 in 0,oi mm., forming obliquely de- 

 cussating lines and alternating in double rows with the costse. 

 Connecting zone with several longitudinal rows of short strise, about 

 25 in 0,01 mm. — Amphipr. latestr. Br^b. in Ktttz. Sp. Alg. p. 93. 

 Navic. convexa W. Sm. B. D. I p. 49 PL XVI f. 136 (18,53). ScoUo- 

 pleura latestriata V. H. Syn. p. Ill PL XVII f. 12. 



Marine: North Sea (Sweden! England! Belgium!), Caspian Sea 

 (Grun.). Atlantic coasts of North America! "West Indies! California! 



Var. Amphora Cl. (1892). — V. asymmetripal, with a more 



convex dorsal side. Median line curved, with the terminations 



Scoliotr. latestr. var. Amjthora Cl. Diatomiste I p. 78 PL 



S. latestriata, 500 times magnified. 



directed towards the same side. 

 XII f. 13. 



Marine: Long Island Sound, New York! 



I have only seen detached valves, of this variety, so I do not know whether both valves 

 have the median lines on the same side of the frustule or not. 



2. S. Grilliesii Cl. a. Comber N. Sp. — V. convex, linear, tapering at the somewhat rounded 

 ends. L. 0,2; B. 0,06 mm. Median line straight (sigmoid at the ends?). Central nodule small; its 

 median pores turned in opposite directions. Axial and central areas indistinct. Costse 7 in 0,oi mm. 

 a little closer towards the ends, parallel, somewhat convergent at the ends, crossed by a longi- 

 tudinal keel, enclosing a furrow broader than a half of the breadth of the valve. The costse 

 alternate with double rows of puncta, about 14 in 0,oi mm., forming longitudinal undulating rows. 

 - PI. I f. 16. 



Marine: Jamaica (Comber ColL)! 



This species, named in honour of Captain Gillies, who procured the material, is a very 

 characteristic, large form, of which fragihents only have been found. The median line seems to be 

 curved, probably in contrary directions, at the ends. The median pores have the same charac- 



