128 THE DIATOMACE^E OF PHILADELPHIA AND VICINITY 



SURIRELLA FEBIGERII LEWIS 



Valve ovate-lanceolate; costse about 2V in 10 n with punctate interspaces extending 

 half the distance toward the median hyaline area, which is divided longitudinally on each 

 side of the narrow pseudoraphe by two longitudinal bands composed of short, transverse, 

 irregular, punctate lines. 



Along the coast. 



PI. 36, Fig. 3. 



SECTION 4 (STENOPTEROBIA) 



SURIRELLA ANCEPS LEWIS 



Frustule linear, straight or nearly so; valve sigmoid with rounded apices; costs mar- 

 ginal, nearly obsolete; stria? distinct, about 15 in 10 n; pseudoraphe wide. L. to 320 M- 

 Hammonton Pond and Tom's River, N. J. 

 PI. 34, Fig. 2. 



SURIRELLA INTERMEDIA LEWIS 



Frustule linear, straight, widened at the truncate ends; valve linear, sigmoid, taper- 

 ing to the sub-acute ends; costse about 5 in 10 n; striae about 20 in 10 M- L- variable. 



Hammonton Pond, N. J. 



PI. 34, Fig. 3; PI. 39, Fig. 9 (zone view). 



This, perhaps, is forma sub-acuta Fricke. 



Fig. 7, PI. 34, is probably a small form of S. intermedia, from Willistown, Pa. It 

 resembles a Nitzschia. 



SURIRELLA DELICATISSIMA LEWIS 



Frustule linear, rounded at the ends; valve linear-lanceolate, sometimes very slightly 

 constricted in the middle, with acute apices; costse, 5 in 10 M; strise about 20 in 10 n; pseudo- 

 raphe well defined, lanceolate. L. to 90 n. 



Fresh water. Newt own Square. 



PI. 34, Figs. 5 and 6 (small forms). 



SURIRELLA ARCTISSIMA A. S. 



Valve linear, tapering to the sub-acute ends; costse marginal, 5 in 10 n; strise, 18 in 10 n; 

 pseudoraphe not evident. L. 184 jt. 



May's Landing, N. J. 



PL 34, Fig. 4. 



Fig. 10, PI. 39, is a small form from Newtown Square, Pa., in which the length is 86 n, 

 the costse 5 and the striae 16 in 10 p. 



PODOCYSTIS KUETZ. (i&44) 

 (pous, a foot, and cystis, a bag) 



Frustules cuneate, similar to Surirella, but attached by short stipes to other algse; 

 valve obovate. 



