72 



p. T. CLEVE, SYNOPSIS OF THE XAVICULOID DIATOMS, 



To this genus probably belongs Stauroneis decora Grev. (T. Bot. See. of Edinb. Vol. VIIT 

 p. 23G PI. Ill f. 11) from New Caledonia. It is very transparent, lanceolate, in lengtli 0, u mm. 

 and has a short staiiros not reaching" the longitudinal ridges. 



Scoliotropis Tl. N. G. 



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

 On both sides of the median line is a longitudinal line. Strncture double: coarser transverse costa^ 

 and finer puncta, disposed in oldi([uely decussating rows. Connecting zone with longitudinal rows 

 of short striffi. 



This genus has been formed for Srolio2^Jciira latcstriafa Grun. as this form is entirely 

 different from the true Scolio])leura-forms in its structure, which is the same as in Go)iipJioiieis, 

 and in the com])lex nature of its connecting zone. Later on another, very interesting species, 

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



The frustules of S. Jatrsfriata have ahmg the connecting zone 

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

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

 the central plasma-mass. 



1. S. latestriata Bri^r. (1849). — V. linear, narrowed at the 

 cuneate ends. L. 0,i to 0, is; B. 0,02.^ mm. Median line strongly 

 sigmoid. Structure: strong costte, 7 in 0,01 mm., transverse, trough- 

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

 cussating lines and alternating in double rows with the eostae. 

 Connecting zone with several longitudinal rows of short stria'. al)out 

 25 in 0,01 mm. — Anqihipr. Intestr. BriSib. in Klitz. Sp. Alg. p. 9;>. 

 Navic. convexa W. Sm. B. i). 1 p. 49 PL XVI f. 13r. (1853). Srollo- 

 phnra latestriata V. H. Syn. p. Ill PI. XVII f. 12. 



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

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

 Var. Amphora Cl. (1892). — V. asymmetrical, with a moi'c 

 convex dorsal side. Median line curved, with the terminations 

 directed towards the .same side. — ScoUotr. latesfr. rar. Amphora Cl. Diatomiste I p. 78 PI. 

 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 frustnle or not. 



2. S. Oilliosii Cl. a. Comber N. Sp. — V. convex, lineai-, tapering at the somewhat rounded 

 ends. L. 0,2; B. 0,00 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 0,01 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 costa; 

 alternate with double I'ows of puncta, about 14 in 0,01 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 fragments 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- 



S. Jdlcsfrinfd, l")!)!' tiniPS maKiiififtil. 



