182 r. T. CLEVK, SYNovsiS OF THE NAVICULOID DIATOMS. 



sents C. hritannka (the upper valve seems to be some Coscinodisciis). Also C. fratcrna A. S. (Atl. 

 CLXXXIX f. 27) seems to be a form of (J. hritannica. 



2. {]. costatjl Gke(4. (1N55). — More or less elliptical to orbicular. Upper V. with narrow 

 axial area and strong, transverse costee, alternating with double^ rows of obliquely arranged puncta. 

 Lower V. with the median line reaching nearly to the margin. Axial area narrow. Central area 

 transversely dilated to a fascia narrowed outwardly. Stri;v radiate, distinctly punctate. 



Var. typico Cl. — L. 0,oi5 to 0,o38; B. (),()09 to (),oi8 mm. Upper V. with linear axial 

 area connected with the margin by strong costa', 5 to (i in 0,oi mm., alternating with double 

 rows of puncta, forming oblique lilies, about 17 in (),ui mm. Lower V. witli indistinct axial area 

 and transversely dilated central area. StriiB 15 in U.oi mm. slightly radiate and distinctly punc- 

 tate; puncta about 16 in 0,oi mm. — C. costata Greg. T. M. S. Ill p. 39 PI. IV f. 10. Vol. V 

 p. 68 PI. I f. 27. A. S. Atl. CLXXXIX f 6, 7. V. H. Syn. PI. XXX f. 11, 12. Snrirella quar- 

 nerensis Grun. Verb. 1862 p. 456 PI. IX f. 10 (1862). lUiaplioneis scutelloides Grun. Verb. 1862 

 p. 383 PI. IV f. 34. 



Marine: Arctic America! Greenland! Davis Straits! Canada! Spitsbergen! Fin mark! Behring 

 Island! North Sea! Mediterranean Sea! Adriatic! Auckland (Grun.). 



Var. he.raf/ona Grun. (1881). — V. broad, linear, with cuneate ends. L. 0,015 to 0,02; 

 B. 0,00'." mm. Costse of the upper valve 8 in 0,0 1 mm. — C. costata var. hex. Grun. V. H. Syn. 

 PI. XXX f. 15 to 17. 



Marine? 



Var. pacifica Grun. (1867). — Elliptical. L. 0,o2 7 to 0,0^; B. 0,oi,5 to 0,03 5 mm. Upper 

 V. with linear axial area and strong costfe, 5 to 6 in 0,oi mm., radiate at the ends, crossed on 

 both sides of the area by a longitudinal line and alternating with double rows of jjuncta, 12 to 

 16 in 0,0 1 mm. Lower N. with transversely dilated central area connected with a marginal blank 

 band, crossing the faint and finely punctate striie, about 8 in O.oi mm. — C. pacif. Grun. Novara 

 p. 11 PI. I f. 10. V. H. Syn. PI. XXX f. 13, U. C. Impvmtyix A. S. Atl. CLXXXIX f. 11 to 

 15 (1894). C. Janischii A. S. Atl. 1. c. f. 33? C. exoptata A. S. Atl. CXC f. 31? C. pnestans 

 A. S. Atl. CXC f. 32? 



Marine: Ceylon! Magellans Straits! Chile (Grun.), Oamaru, fossil! 



Var. herguelensis Pet. (1888). — Elliptical to orbicular. L. 0,055 to O.i; B. 0,o.t to 0,o85 

 mm. Upper V. with narrow, linear axial area, (/ostse 4 to 6 in 0,oi mm. alternating with double 

 rows of puncta, about 10 in (),oi mm., forming oblique lines. Lower V. with the median line 

 ending near the margin. Axial area very narrow. Central area a transverse, outwardly narrowed 

 fascia. Strite 4 in Ooi mm. composed of double rows of puncta, 10 to 12 in 0,oi mm. and crossed 

 near the margin by a narrow blank band. — C. kcrffuelensis Pet. I), de Cape Horn p. 116 PI. X 

 f. 5. A. S. Atl. CLXXXIX f. 9. C. liegina Johns. M. J. VIII ]>. 13 PI. I f, 12? (J. cxfraragans 

 Jan. a. S. Atl. CLXXXIX f. 2H to 32. 



Marine: Kerguelens Land! Magellans Straits! 



The var. kcrgueleusis cannot in my opinion be separated as a distinct species from (J. costata, 

 however ditferent it may look at the first glance. The important characteristics are the same for 

 both, and the ditferences consist only in size, number of costfe and striee. The difference in size 

 is enormous, C. kcrgiudensis being gigantic compared to 6'. costata. 



Heteroneis Cl. X. G. 



Frustule without rim. Valves very dissimilar, in outline plli])tical or t'lliptic-lanceolate. 

 Upper valve striate or ccstate, with a large area. Ijower valve either without, with uniting 

 axial and central, or witluuit axial and with (iiuidrate central, area. 



