178 p. T. CLEVE, SYNOPSIS OF THE NAVIOULOID DIATOMS. - 



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

 — — rur. robusta Pant. Ill PI. XXIII f. 3r)(). 

 C. marina Pant. Ill PI. XIX f. 274 (Amphora aiigusta var.?). 

 C. ohtusa Pant. Ill PI. V f. 70. 

 C. pachyptera Pant. PI. XXI f. 304, 31 fi. 

 C. Feragcdli Pant. Ill PI. XLII f. 584. 



C. perfect a Pant. Ill PI. XVII f. 241) (C. oymbiformis vai'.?). 

 C. lAutonica Pant. Ill PI. XX f. 2'J7 (C. aspera var.?). 



C. prcEclaru Pant. Ill PI. XXXVI f. 512 (resemble.s C. lanceolata but has closer stria-). 

 C. Bahoczyana Pant. Ill PI. VIII f. 121 (C. Oistula var. maculata?). 

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

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

 C. Szoniaghii Pant. Ill PI. X f. 1(11 (Ampliora augusta vai'.?). 

 C. suams Pant. Ill PI. XV f. 229 (akin to ('. leptoceras?). 

 C. tnryida Pant. Ill PI. VI f. 103 (C. parva?). 

 C. vaVula Pant. Ill PI. IX f. 154 (C. as])era var.?). 

 C. reyeta Pant. Ill PI. XXIV f. 359. 



Gomphonema Aoardu (1824). 



Valve more or le.ss elongated, olavate, or a.symmetrical to the transver.se axis. Structure: 

 transverse slightly radiate strict; or rows of p\;ncta. Connecting zone not complex, broader in the 

 upper than in the lower end. Cell-contents a single clironiato])li()re, leaving only a narrow- pai'ietal 

 plasmaband along one side of the zone, deeply sinuose below the median line, (^n conjugation two 

 auxospores 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 Ban u. Kntw. p. rSS). 



The large G. geiuinafnm was observed as early as 1773 l)y 0. P. Muller, wlio named it 

 Vorfieella pyraria. The genus Gomphonema was established 1824 by Aoardh for two species, and 

 since then a large number of species have been formed by KnKENiiER(t, KiiTZiNG and others, unfort- 

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

 connected frustuies, Ehrenberg created (1S43) the genus Sphenosini. Kutzing founded (1844) the 

 genus SpheneUa for free-living forms and Rabenhorst (1853) the genus (roniji/ioriella 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 systematical!}' the known species of Gomphonema was made (1878), by (irRrNOM' 

 in his descri])tion of the alg;e 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 tbese forms, and place them in a .-separate genus Goniplioxeis. Recently 

 Brun has described, as (i. caiifalicuiit, a species, which seems to be allied to Gomphoneis, as it 

 shews across the strite a longitudinal line, but the striation of this species is in all other re.spects 

 ipiite different from that of (ifomphoneis. 



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

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

 end, or (ijicx, 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 (Jymbellit. Some varieties are even slightW cymbelliform. In many species there is on 

 one side of the central iiinlnlc an isolated ]iuiir1iiiii, or sHyiiKi. as in several Cvmbelhc, and in othei's 



I 



