308 DEE1*-SEA DIATOMACK-E ISIANN. 



Tills (liatoni is identical with tho ti,i;iii'(' above relbned to, but that it 

 should be giveu tSuiith's name of X. {Pin)i.tihtri(() disttins is doubtful. 

 That author was very strict on the point of nioniliform costa', separat injj; 

 NaricuJa from Finnuhiria on this one characteristic. Jlence he would 

 never have called a diatom with the evident naviculoid markings of 

 this one " rinnularia.'" IJesides, his description of /*, (li.slans states 

 that the apices are "acute" (p. 50), which is not the case here. 



Navicula exemta A. S. (Sclimiilt's Atlas, pi. 6!), tigs. 13, 10.) Froqiiciit. 

 Naviculafirina Kuwar. tiiinescens (Jruu. (Schmidl's Atlas, pi. I'J, lij^. 10. ) Soarco. 

 Navicula fusca Gicji-. var. delicata A. S. (Siluiiidt's Atlas, pi. 7, lig. 1.) Starce. 



Thoujili this form is analogous to X. smithii Breb., it differs in being 

 not comiKMind punctate in its costa', but strictly luoniliforin costate; 

 also in having several rowsof costiv at each end of the frustule i)arallel 

 with the long diameter. Kalfs distinguishes between the above in 

 Pritchard's Inf., j). 81KS. 



Navicula gastruin var. placentula Elirl). (Van llcnnk's Syii., pi. S, iigs. 2(i-2S; 

 Cleve's (1880) "Arctischcn," pi. 2, lij,'. oO; rrilchaKr^ Inl'iisoria, p. DOG.) Scarce. 



Ehrenberg's N. gasfrion and X. pUurntHJa are virtually the same 

 diatom. They are considered identical by Ivalfs, yet, as placcntida is 

 generally figured with narrower and more tapering apices thaii f/astnon, 

 I have given both names, making the later a variety of the earlier form. 



Navicula gianulata I?rcb. (Schinidt's Atlas, ])1. (5, iigs. ir>, 1(>.) Scarce. 

 Navicula Hennedyi W. S. (Schmidt's Atlas, ])1. ;>, Iigs. 3 aud 18.) Scarce. 

 Navicula hunierosa HrcV), (Van lltMirck's Syn., i»l. 11, lig. 20.) Frequent. 

 Navicula interrupta W. S. (Schmidt's Atlas, pi. 15, lig. 72; Smith's 11. P., ])1. 10, 

 lig. 180.) Scarce. 

 Kutzing has given the same na.me to a wholly dilVerent form. ISee 

 his IJacillaria, p. lOO, pi. 20, tig. 1);5. 



Navicula irrorata Grev. (Schmidt's Atlas, ])1. 2, Iigs. 10, 22, 23.) Very scarce. 

 Navicula lineatR Donk. (?) (Schnudt's Atlas, pi. (JO, lig. 31.) Scarce. 



This diatom, which is accurately illustrated by the above figure, is 

 not the real X. lineata of J)onkin, as is seen by coini)aring the above 

 with tig. 8 on pi. 1 of ])onkin's " British Diatoms." It is similar to A. 

 yciimidt's X. (lii/rnlicns ; but might perhaps receive a new name. 



Navicula lyra Ehrb. (Schmidt's Atlas, pi. 2. Iigs. IG, 24-25, «'tc. Van llcnrck's 



Syn., pi. 10, tigs. 1-2.) Connimu. 

 Navicula lyra, var. dilatata A. S. (Schmidt's Atlas, ])1. 2, fig. 2().) Scarce. 

 Navicula lyra, var. elliptica A. S. (Schnudt's Atlas, pi. 2, Iigs. 29-34.) Frequent. 



These varieties oi X. lyra Ehrb. are all unimportant. 



Navicula major Ornn. (Schmidt's Atlas, pi. 42, figs. 8-10. Van Heurck's Syn., pi. 



r>, lig. 3.) Scarce. 

 Navicula niesolepta Ehrb., var. stauroneiformis Greg. (Van llcnrck's Syn., pi. 6, 



lig. l."". ) N'cry scarce. 

 Navicula pennata A. S. (Schmidt's Atlas, pi. 18, Iigs. 41-43.) Fre(|uent. 

 Navicula preetexta Khrb. (Schmidt's Atlas, i)l. 3, Iigs. 30-34.) Scarce. 

 Navicula rhomboides Ehrb. (Van llcnrck's Syn., i)l. 17, fig. 1.) Scarce. 



The jiiaking a m'w genus " Van Hcurclia^^ for this diatom is to bo 

 deprecated . 

 Navicula rostellata Kg. (Van llcnrck's Syn., pi. 7, figs. 23-24.) Frequent. 



