^"^iB'Js!"'] PROCEEDINGS OF THE NATIONAL MUSEUM. 309 



This is very near some forms of J\\ raritoi.s Greg. 5 but tlie cost;e do 

 not contiiiiic "radiant from (;eutral jiodulc," but midway between it and 

 tlie apices become strictly transverse. 



Navicula Schultzei Kaiii. ("Atlantic City Diatoms" in tlio Tony Botanical Bul- 

 letin, pi. 8!», fig. 2.) Very scarce. 



Tliis diatom, though similar to N. maculata Edw,, is probably dis- 

 tinct. This conclusion is reached, not from drawings, but from a care- 

 ful comparison and measurement of the original diatoms named. 



Navicula serians Kg. (Van Heiirck's Syn., pi. 12, lig. 7.) Scarce. 

 Navicula Smithii lireb. (Van Heurck'H Syn., i»l. 9, fig. 12; Scbmidt'H Atlas, pi. 7, 

 lig. 22.) Common. 



This beautiful diatom presents several unimportant varieties in this 

 gathering. 



Navicula splendida Grog. (Schmidt's Atlas, pi. 13, fig. 32.) Frequent. 

 Navicula subcincta A. S. (Schmidt's Atlas, jil. 1.3, fig. 41.) Scarce. 

 Navicula suborbicularis Greg. (Schmidt's Atlas, pi. 8, figs. 1-6.) Scarce. 

 Navicula transfuga Grun. (Cleve's "Vega," j)l. 35, fig. 15, p. 511.) Scarce. 

 Navicula Weissflogii A. S. (Schmidt's Atlas, pi. 12, figs 20, 32.) Very scarce. 

 Nitzschia amphionys Grun. (Van lleurck's Syn.,pl. 56,figs, 1-6.) Frequent. 



Tlie creating a new genus, "Hantzschia," for this diatom is wholly 

 unnecessary. 



Nitzschia gracilis Hantzsch. (Van lleurck's Syn., pi. 68, fig. 11.) Frequent. 

 Nitzschia marina Grun. (Van lleurck's Syn., pi. 57, figs. 20-27.) Very conimou. 



The variety found in this gathering differs from the type in a de- 

 cidedly coarser marking, the monils being evident under a quite low 

 power of magnification. Its apices also are more regularly tapered. It 

 is found in an endless variety of lengths, but retains a constant width in 

 all cases. It is iirobably the same as ^'■Hynedra atlantica" of Castracane; 

 see Challenger Exp., p. .^3, pi. 25, fig. 10. 



Nitzschia marginulata, var. didyma Grun. (Van lleurck's Syn., pi. 58, fig. 14.) 



Scarce. 

 Nitzschia palea W. S. (Van Heurck's Syn,, pi. 09, figs. 22-^. 29, 31.) Frequent. 

 Nitzschia panduriformis Greg. (Van Heurck's Syn., pi. 58, figs. 1-6.) Fre((uent. 

 Nitzschia punctata Gnm. (Van Heurck's Syn., pi. 57, fig. 2.) Very scarce. 



This IS W. Smith's " Tryhlionella punctataJ'^ It very evidently be- 

 longs to the Nitzschia; . 

 Nitzschia salinarum Grun. (Van Heurck's Syn., pi. 57, fig. 18.) Scarce. 



It is doubtful if the separation of this form from Smith's N. {Tryhlio- 

 nella) levi(leiiNi,s is justifiable. 



Nitzschia sigma W. S. (Van Heurck's Syn., pi. 65, figs. 7-8.) Freciucnt. 

 Nitzschia thermalis Grun, (Van Heurck's Syn., ])1. 59, figs. 15-19.) Scarce. 

 Pleurosigma afilue Grun. (Van Heurck's Syn., pi. 18, fig. 9.) Frequent. 

 Pleurosigma inflatum Shad. (Mujbius's Plates, pi. 3, fig, 9. Pritchard's luf., p. 



918.) Common. 

 Pleurosigma KUtzingii Grun. (Van Heurck's Syn., pi. 21, fig. 14.) Frequent. 



This is certainly identical with /*, (fracileittum llaben., but the sug- 

 gestion in Habirshaw's Catalogue, and in CIcac's (1880) "Arctischen," 

 that it is a variety of P. Speneerii Grun., is probably incorrect. Great 



