THE DIATOMACE.E OF PHILADELPHIA AND VICINITY 15 



MELOSEIRA GRANULATA (EHR.) RALFS 



Frustules cylindrical, robust, 5-18 ft in diam., with large granules in longitudinal, some- 

 times spiral, lines, variable in size and arrangement in the same filament. Valve in valve 

 view with scattered puncta. Variable in relative width and length, passing to M. crenulata. 



Gaillonella granulata Ehr. 



Orlhosira punctata Wm. Sm. 



Fresh water. Fossil at Coldspring, L. I. 



PL 1, Fig. 10. 



MELOSEIRA CRENULATA (EHR.) KUETZ. 



Frustules cylindrical, with furrows on each side of the suture, 10-20 /j. in diam.; puncta 

 in longitudinal rows. Margins of valves denticulate at the junction of the frustules; valves 

 with puncta scattered at the centre, radiate at the circumference. 



Common in fresh water; quite variable in size. 



Gaillonella crenulata Ehr. 



Orthosira orichalcea Wm. Sm. in part; not Conferva orichalcea Mertens or Gaillonella 

 aurichalcea Ehr. and Bailey. 



PL 1, Figs. 1 and 2. 



MELOSEIRA ROESEANA RAB. 



Frustules cylindrical, constricted toward each end, with coarse, longitudinal striae; 

 valve convex, striae punctate, radiating, with several large granules at the centre. Connec- 

 tive zone with longitudinal rows of fine puncta. Diam. 12-45 /*. 



Orlhosira spinosa Grev. 



Fresh water. Media, Pa. (Palmer ) ; not common. 



PL 1, Figs. 5 and 6. 



MELOSEIRA ROESEANA VAR. EPIDENDRON (EHR.) GRUN. 



Frustules denticulate at the margin; valve with coarse granules at the centre from which 

 radiate lines of fine puncta. 



Wet rocks of the Wissahickon. 

 PL 1, Figs. 3 and 4. 



MELOSEIRA UNDULATA (EHR.) KUETZ. 



Frustules single or in twos, usually broader than long, constricted near the margin. 

 Valve with six to twelve internal projections forming with the outline of the constriction 

 of the valve a polygonal figure within the circumference. Surface of the valve with radiat- 

 ing lines of puncta disappearing toward the centre, at which are numerous coarse puncta. 



Meloseira gowenii A. Schmidt. 



Blue clay of Philadelphia, especially common at Twelfth and Market Sts. 



PL 1, Figs. 15, 16, 17. 



MELOSEIRA SULCATA KUETZ. 



Frustules quite robust, with diam. several times the length, deeply furrowed at the 

 margin, areolate and punctate. Valve with radiating striae disappearing toward the centre, 

 and with a double row of cells near the margin, the outer one having the appearance of a 

 crown of teeth. 



Gaillonella sulcata Ehr. 



Paralia sulcata (Ehr.) Cleve. 



Paralia marina Heib. 



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