130 THE DIATOMACE.E OF PHILADELPHIA AND VICINITY 



CAMPYLODISCUS ECHENEI3 EHR. 



Valve sub-orbicular, saddle-shaped; costse indistinct, short, marginal; rows of round 

 or elongated puncta converge toward the lanceolate, hyaline median space. Diam. 80- 

 140 p. 



Campylodiscus argus Bail. 



Blue clay. Reservoir at Thompson and Twenty-sixth Sts., Phila. 



PI. 37, Fig. 6. 



This form, usually considered as brackish and marine, is occasionally found in fresh 

 water. According to Deby, it is fossil in the "Champlain deposit of N. A." 



CAMPYLODISCUS HIBERNICUS EHR. 



Valve irregularly orbicular; costse, 40-60, about 2 in 10 ju, wide at the margin and 

 attenuated toward the centre which is somewhat quadrate; the radials rough with minute 

 apiculi. 



Pensauken, N. J., artesian well. 



PL 37, Fig. 5. 



