27 



Ilimantidiiim arcus. 

 Surirelhi biscriata, W. S. variety. 

 Tabellaria trinodis. 

 Synedra ulna. 



Gomplioiiema geminatuin, acuiiiiiiatiiin, coroiiatuni, turgidiiin, 

 gracile, o. 



Cocconenia lanceolatura. 

 Cocconeis placentula. 



FAMILY NAVICULACE^. 



Navicula dilatata, araphigomphus, fusidium, dicephala, legu- 

 men, biceps, platalea, 7. 



Piiinularia legumen, dactylus, digitus, macilenta, decurrens, iii- 

 equalis, termes, major, W. Sm., leptogongyla, viridis, 10. 



Stauroiieis platalea, Elir., pteroidea? lanceolata, Kutz., gracilis, 

 ainphicephala, Baconiana, C. S., nov. spe., pellucida, C. 8., nov. 

 spe., Baileyii, phoenicenteroii ? anceps, isostauron, cardinalis, as- 

 pera, birostris, Ehr., 14. 



Aniphiprora navicularis. 



And several undetermined species of Synedra, Navicula, Pin- 

 nularia, Himantidium, Cymbella, Fragillaria, Diatoma ? Cocco- 

 neis, Tabellaria, Homoeocladia, Melosira. 



The description of the two new species is as follows : 



Stauroneis Baconiana. Stauroneis medium size ; side 

 view beaked ; beaks produced ; apices rounded ; stauros extends 

 to the margins ; very fine transverse lines radiating from centre. 



Front view (of Wm. Smith, lateral of Ehrenberg) not quite so 

 wide as side view, and the beaks have a very slight sigmoid 

 curve. 



Lon. .12 to .14 millimetre ; side view Ion. 6^ times the breadth ; 

 front view 6 times the breadth. Abundant. 



Outline of side view resembles S. Sieboldii, Ehr., but is much 

 more slender, the longitude of Sieboldii being 4 times the breadth. 

 Front view of Sieboldii unknown. 



Stauroneis pellucida. Very small. Side view: outline 

 of sides a regular curve, apices truncated and broadly rounded, 

 stauros broad, nearly square, and does not extend to the margins. 



