178 p. T. CLEVE, SYNOPSIS OF THE NAVICULOIT) DIATOMS. 



C. lanceolata var. fossilis Pant. Ill PI. XXIII f. 344. 

 — — var. rohusta Pant. Ill PL XXIII £ 350. 

 C. marina Pant. Ill PL XIX f. 274 (Amphora angusta var.?). 

 C. obtusa Pant. Ill PL V f. 79. 

 C. pachyptera Pant. PL XXI f. 304, 316. 

 C. Feragalli Pant. Ill PL XLII f. 584. 



C. perfecta Pant. Ill PL XVII f. 249 (C. cymbiformis var.?). 

 C. plutonica Pant. Ill PL XX f. 297 (C. aspera var.?). 



C. prceclara Pant. Ill PL XXXVI f. 512 (resembles C. lanceolata but has closer strise). 

 C. Rahoczyana Pant. Ill PL VIII f. 121 (C. Cistula var. maculata?). 

 C. simplex Pant. Ill PL XXI f. 308 (C. ventricosa?), 

 G. Staubii Pant. Ill PL VIII f. 131 (C. leptoceras var.?). 

 C. Szontaghii Pant. Ill PL X f. 161 (Amphora augusta var.?). 

 C. suavis Pant. Ill PL XV f. 229 (akin to C. leptoceras?). 

 C. turgida Pant. Ill PL VI f. 103 (C. parva?). 

 C. valida Pant. IH PL IX f. 154 (C. aspera var.?). 

 a vegeta Pant. Ill PL XXIV f. 359. 



Gomplionema Agardh (1824). 



Valve more or less elongated, clavate, or asymmetrical to the transverse axis. Structure: 

 transverse slightly radiate strise or rows of puncta. Connecting zone not complex, broader in the 

 upper than in the lower end. Cell-contents a single chromatophore, leaving only a narrow parietal 

 plasmaband along one side of the zone, deeply sinuose below the median line. On conjugation two 

 auxoapores are formed by two mother-cells, parallel to them. The plane of division of the primordial 

 cell is at right angles to the plane of division of the mother-cells (Pfitzer Bau u. Entw. p. 88). 



The large G. geminatum was observed as early as 1773 by 0. P. Muller, who named it 

 Vorticella pyraria. The genus Gomphonema was established 1824 by Agaedh for two species, and 

 since then a large number of species have been formed by Ehrenberg, Kutzins and others, unfort- 

 unately founded on trifling characteristics. For forms living, as Diadesmis, in bands of closely 

 connected frustules, Eurenberg created (1843) the genus Sphenosira. Kutzing founded (1844) the 

 genus Sphenella for free-living forms and Rabenhorst (1853) the genus Gomphonella for forms, 

 which live in gelatinous masses. Heiberg (1863) maintained, with justice, that these genera are 

 not admissible, as they are founded on characteristics, which occur in the same species. An 

 attempt to arrange systematically the known species of Gromphonema was made (1878), by Grunow 

 in his description of the algse of the Caspian Sea, and since then he has given a number of most 

 valuable figures in Van Heurck's Synopsis Plates XXIII, XXIV and XXV. As among them there 

 are several species from America, which, while having the general outline of Gomphonema, differ in 

 their structure, and in the presence of longitudinal lines, similar to those of Scoliotropis and 

 Caloneis, I now exclude these forms, and place them in a separate genus Gomphoneis. Recently 

 Brun has described, as G. cantalicum, a species, which seems to be allied to Gomphoneis, as it 

 shews across the strise a longitudinal line, but the striation of this species is in all other respects 

 quite different from that of Gomphoneis. 



The valve of Gomphonema is asymmetrical to the transverse axis, and is usually broader 

 in the upper portion, with a wedge-shaped lower end. The central nodule is nearer to the tipper 

 end, or apex, than the lower, or basis. Many species are asymmetrical also to the longitudinal 

 axis, but in a less visible degree, as Pfitzer first pointed out, with a parallel asymmetry, like that 

 of the Cymbellse. Some varieties are even slightly cymbelliform. In many species there is on 

 one side of the central nodule an isolated punctum, or stigma, as in several Cymbellse, and in others 



