388 



JOHS. HOYi: PKTKHSKN 



Fig. U. 



Xtiriciild 

 bnjo])hiln 

 HoyeP 11. s|). 

 "x ll'OO). 



Navicula bryophila Hove \\ ii. sj). 



Valva lincari. apicibus rostratis, lonj^. 1(5 //. Int. :}.7 /', .striis 

 (lelicalis.siiuis. vix visil)ilil)iis circitcr 35 in 10//. radiantibiis. 

 .\ica ajiicali an^iisln. i'if^. 13. 



K. Ic-i-1. 7. 2.'). 



l-"()Uii(i among niosscs in Iwo placcs Nvliich wcrc oflcn 

 (lam|) with tricklinj^ watcr. It is hardly a si)t'cies tliat will 

 wilhstand imicli desiccation. 



The valve is verv hyaline and Ihe stiiæ are so line lliat 

 they are hardly visible and llieir exact nuniber can scarcely be aseer- 

 taiiicd. They secni to beeonic closer towards tlie apices. 



NaviciiUv mesoleiæ Cl. 



Navicula bidentula iSoye P. n. sp. 



Valva lineari. siibcapitata, in medio inllata, iitrin(|iie bi- 

 dcnilata. Lonj^. 17//. lat. 3.5//. striis invisibilibus. Area api- 

 cali angusla, area cenlrali in lasciani transapicaleni dilatata. 

 Fig. 14. 



N.lcel. 215. 217. 



Fig 14. 

 SoviciiUi 



riie valve of this small, very ])eculiar species ot which gQ^el'. n.sp 

 I have only seen few specimens has the same outline as (x riOO). 

 N. Lcuiersledlii Cl. (Syn. I, p. 141 ; La ger stedt 1873, PI. II, 

 fig. 12 , but the striation is so fine in the present species Ihat I have 

 not been able to count the striæ. There seems to be a transapical 

 area, and the frustule is much smaller. 



Only t'oiind in the ravine Stora (Ija near Myvatn. 



Navicula Caloneis?) Borrichii Boye P. var. subcapitata Boye P. 

 Boye Petersen 1915, p. 285. 11-^. 3. 



E. Icol. L. 121. 



Only known as an aerial alga, and only Trom nenmark. Bolh Ihere 

 and in Iccland it was met with under such circumslances that it must be 

 jiresumed to make great demands on the nulritious matter of the earth 

 and must likewise be supposcd to belong to tiie species lluit will sur- 

 vive nuuii desiccation. 



— — var. undulata n. var. 

 Valva lateiiiius Iriundulatis, long 21//, 

 23 in 10//. I-'ig. 15. 



N. kel. 182. L. 241. 



lat. 5._' // . striis 



Fil,'. 1.5. 

 \ai'icula 

 Rtirrichii 



Boye P. var. 



iiniliilaid II. 



This form is idenlical with a specimen already mentioned 

 by me (1915, p. 289, as a probable variety of Stauroneis 

 agrestis Boye P. with which, however. it has no conneclion. 

 I have subsecpiently. in the jireparation in which this speci- 

 men occurred, found olher specimens seen in girdle view 

 and showing the struclure peculiar to N. Borrichii. It was 

 found on a luif fence near Skutustaflir and at Ixalivcr on 



var. (XI '-200). Ih c bank of one of tiie hot streams. 



