40 THE DIATOMACE.E OF PHILADELPHIA AND VICINITY 



LICMOPHORA TINCTA (AG.) GRUN. 



Frustules cuneate, narrow, usually found in twos. Valve clavate, hyaline, rather 

 broad at the base; septa moderately deep; pseudoraphe indistinct; stria?, 27 at the base, 30 

 in the middle and 33 at the apex in 10 /*. 



Gomphonema tinctum Ag. 



Along the coast. Abundant from about the middle of July to the middle of August. 



PL 9, Figs. 14 and 15. 



LICMOPHORA BAILEYI (EDW.) GRUN. 



Frustule broadly cuneate or with convex margins, rarely almost orbicular; valve spat- 

 ulate or ovate with slender, produced base; septa very deep; pseudoraphe distinct; strise 

 20 in 10 n. 



Podosphenia baikyi (Edw.) Lewis. 



Long Island Sound and upper coast of New Jersey. 



This form is placed in a doubtful position by Mereschkowsky. As it corresponds more 

 closely to the Paradoxse, it is placed here provisionally. The girdle face and apex of the 

 valve are round, the pseudoraphe is distinct and the septa deep, but the stipe is short. 



PL 9, Fig. 10 and PI. 38, Figs. 3 and 4. 



LICMOPHORA LYNGBYEI (KUETZ.) GRUN. 



Frustule cuneate, slightly rounded at the angles. Valve oblanceolate; pseudoraphe 

 distinct; septa deep; strise, 12 in 10 p. below, and 16 in 10 n above. 

 Podosphenia lyngbyei Kuetz. 

 Along the coast. 

 PL 9, Figs. 3 and 4. 



LICMOPHORA EHRENBERGII (KUETZ.) GRUN. 



Frustule cuneate, broad. Valve obovate-lanceolate; pseudoraphe wide; strise coarse, 

 8 in 10 fi, moniliform. 



Podosphenia ehrenbergii Kuetz. 

 Along the coast. 

 PL 9, Fig. 5. 



MERIDION Ac. (1824) 

 (merizo, I divide) 



Frustules in zone view cuneate, adnate in circular or spiral fascise, at length becoming 

 free. Valve symmetrical with respect to the longitudinal axis, more or less cuneate; costse 

 and strise transverse. 



Chromatophores numerous, small, elongated, in irregular rows on the zone (Pfitzer). 



MERIDION CIRCULARS (GREV.) AG. 



Transverse costse coarse, variable in number and distance apart, sometimes inter- 

 rupted or indistinct; strise interstitial, 16 in 10 p. 

 In springs and small streams of pure water. 

 EchineUa circularis Grev. 



