44 



Amphiprora is founded on ìt (1843, Ab. p. 11 3) is not a species of 

 this genus as now recognized. It is a Navicula of the Pinnularia 

 tvpe or group with pinnules instead of striae. 



The valve is not bent, but the cnds are rounded and the pin- 

 nules coarse, radiant, not as near together aroud the centrai noduie. 

 It seems to be a well marked forni found as yet in the United Sta- 

 tes at present, and Ehrenberg says that it is perhaps a Cocconema, 

 but it cannot be that for the median line is centrai, although there 

 is a form called Cocconema which has the median line nearly cen- 

 trai. It is tìgured in the Mikrogeologie, 1854, T. 16, Ili, fìg. 80, and 

 sequa 1. 



I mcntion it in my Report of specimens of Infusorial Earths of 

 the Pacific Coast of the United States, 1891 in the Am. Jour. of 

 Sci. Voi. XLll, pag. 898, where 1 say it is found common in lacu- 

 strine sedimentary deposit of this country although 1 do not remem- 

 ber to bave seen it in the recent state. 

 Aìiipliora elliptica C. A. A. 



Biddulphia laevis C. G. E. This is a species or form which oc- 

 curs in the Guatemala Diatomite, fresh water, at Quinipiac, Conn., 

 brackish water, between Newark and Elizabeth, N. J., fresh water, 

 in the Passaic River at Newark, N. J., salt water, in New York bay, 

 salt water, and in the Raised Coast Period at Newark, Jersey City 

 and Elizabethport, N. J. and at South Beach, S. I., N. Y., besides 

 at Coccoanut Bay, Fa., Tampa, Fa, and ali along the coast into the 

 Gulf of Mexico. This can be said to be a form which grew in fresh 

 water, brackish and salt water and 1 strongly suspect is developed 

 from Melosira varians. 



Cicconeis placenlula, C. G. E. This is the ordinary form which 

 is so common in almost ali fresh water gatherings. In the llatlield 

 Swamp day it is the ordinary form, but in the Guatemala Diato- 

 mite it is coarser and seens to pass into C. scu/elliim, C. G. E. through 

 C. lineala, C. G. E., which is largcr Ihan the ordinary form. 



C. Scutelliini, C. G. E. One specimen of this form was seen but 

 of course it must be common for 1 examined a small porlion, pe- 

 rhaps a grain of the whole stratum. It was the ordinary form but 

 was coarser than that and somelhing iikc C. Sciitt'lliim. var. orna/a, 

 A. G. 1880-81, Van lleurck Syn. des Diat. de Bel. PI. XXIX, fìg. ò. 



