AUCTORE PROF. lOSEPIlO MESECIIIMO l4l 



Tab. XV. fig. a. b. Frustulum, vigcsics aiictnin. 

 2. c. Pars ciusclem , cenlies aucla. 

 a. d. Fila noimulla , lerccntifs aucla : * (ila O.sill- 

 larlac b rev is , Ktz. 



IllVULARIA CONTARENII , ZaNARD. Lell. II. ji. 5. 



R. (( fvondc planiuscula, lain'i , arbiculata , minutissiina , (icfUf^inom n . 

 Zakard. 



I/ab. Ad sa\a , quibus promiscuc IIilileiil)niii(lia adliacrt-l , arrlo 

 aflixa : CI. Contarini. 



Descript. Frondes minimac, planiusculiie, lineam uiiaiii vi.K diautctro 

 .superaiitcs , orbiculares couflucntcs , aerviginoso-viridcs a saxi siifn'rlicie 

 vix proininulae. Microscopic iiispcclac ct niiniinae qiioque a pluribus 

 siinul coniluentibus constilui dcpreheudimtur , quarum unaquacque (His 

 constat a ccnlro radiantibus , siinplicibus , brevibus , flexiiosis , .saepc 

 spiralilcr lortis , a basi incrassata sursuin attenualis , a[)icc aculis , ai-- 

 ticulis torulosis, diamctro duplo longioi'ibus, amndis iuconspicuis. Vagina 

 exterior teuuissima , obsoleta. Glol)uli basilarcs nulli. Filorum diauielnis 

 ad basim diinidiuin centimillimetrum vix aequat. 



Obs. Summa exterioris adspcctus siniilitudo liuic spcciei cuui Riwi- 

 laria plana , CI. Harvey inest , attamcn microscopicis cliaractcribus loto 

 coelo diflcrunt. 



Rivularia plana , Harv. ( Hook. Br. FI. ) a CI. Desmaziers ( Cryi>l. 

 N.° 808) exhibila , schisto micaceo adnata, frondibus plaiiis , minimis, 

 orbicularibus , confluentibus donatur , quae lamcn dimidium (juoque 

 cenlimctrum diamelro attiugunt ; color obscure viridis ; superficies ae- 

 qualis. Vcrticaliter sectae colore viridi lutescente donatae conspicimitur, 

 et fdis crcctis parallclis slipalissimis , cenlro longioribus, ad ambituni 

 scnsim brevioribus, leviter inclinatis et ad pcriplicriam I'adiantibus. Fila 

 simplicia sunt, vel ad basim obscure dichotoma sensim gradatimquc at- 

 lenuala , apice acuta , articulis omnibus , diamctro duplo longioribus . 

 vel quadripartitis, hinc diamctro dimidio brcviorcs , per paria eviden- 

 tiores ; in nonnullis annuli sive sporangia iiiviccm discrcta ; alias , in 

 fdis fere rcsolutis, sporulae minulissiniae trausversim seriatac; tandem 

 tubo fdi omnino evanido , sporangia libera , rotundato-angulosa in \a- 



