36 Algse, Bacillaiieie, CryptorhaphiJese, Rhizosoleniacese, Rhizosolenia. 



Fam. CHiETOCERACEiE 



Gen. Chaetoceros Ehr., in Ber. Berl. Ak., 1841, p. 198. 

 Frustula obloriga, medio plerumque tumida, levia vel punctata in 

 filamentum longum cylindraceum conjuncta, valvae convexae ellipticae 

 vel subcirculares, cornubus plus minus elongatis, filamentosis (per quse 

 frustula adhasrent) donatas; zona connectivalis (teste Schiitt) plerum- 

 que singula, valvis multo magis delicata, breve cylindracea sectio- 

 nem ellipticam vel suborbicularem vel oblongam pniebens. 



1. Chaetoceros Wighamii Brigthw., in Micr. Journ., 1850, p. i08, t. VII, 12^ 

 f. 10-36. Castrac, Atti Acc. Pont. N. Lincei, 18 Marzo 1877, p.245. — 

 Frustulis in filamenta longa conjunctis, valvis ovalibus ad 20-25 y.. 

 longis, raro tantum 5-6 a. latis, convexis, superficie spinis parvis 

 obsita, utroque fine cornubus binis longissimis filamentis acatis in- 

 structis. 



lu tripoli ad montes Labronicos Tuscice (Castrac). 



Ad geuus Chcetoceron Ehr. verisimillime referri potest : Actini' 

 scus Sirius Ehr., Leb. Krerd., 1840, p. 70. Sauvage, Ann. Sc. Nat. 

 IV, 1873, p, 68. — Radiis 6 acutis, basi alatis. 



In tripoli raessiniauo «Licata» insulae SicilicB (Sauvage). 



Fam. RHIZOSOLENIACE^ 



Gen. Bhizosolenla Ehr., Amer., 1843 p. 134;Ber. Berl. Ak., 

 1844, p. 88 '). 



Frustula ssepe imperfecte silicea, cylindracea, aunulata (h. e. 

 laminis adparenter irabricatis polygoniis coraposita) cohaerentia, elon- 

 gata, apicibus conformibus calyptneformibus spina seu raucrone ter- 

 rainatis. 



1. Rhizosolenia setigera Brigthw., in Micr. Journ., 1858, p. 96, t. V, 130 



f. 7. Castrac, Atti Acc. Font. N. Lincei, 18 Marzo 1877, p. 245. 

 — Frustulis subcylindraceis 15-20 [j.. latis, circiter 5-15-ies lon- 

 gioribus, articulis (laminis) tantum sub luce obliqua visibilibus, 

 striis delicatissimis; appendice callyptrasformi seta tenui plerum- 

 quo cnrvata longissima terminatis. 



In tripoli ad montes Labrouicos Tuscice (Castrac). 



^) De lioc j^cnore cfr. moiiograpliiam clari H. Peragallo iii Diatomiste 1892, 



