Algsd, Bacillariese, Cryptorhaphidese, Coscinbdiscacese, Coacinodiscug. 27 



p. 13. — Frustulis e sphaerico-compressis, densissime connatis, dia- 

 metro subaequalibus vel parum brevioribus, fronte, ad peripheriam 

 evidenter, centrum versus subtiliter radiatim striatis; valvis de- 

 presso-hemisphaericis, celluloso-punctatis, sub commissura sulcatis, 

 diam. 20-40 p.. 



In marga « Caltanisetta » insulae Sicilice (Ehr.); in schisto sili- 

 ceo tortoniano «Messina» ejusdem insulae (Nicotra); in marga gy- 

 psifera tortoniana « Capo S. Marco » insube Sardinioe (Mar. et 

 Par.). 



Gen. Cyclotella Kuetz., Syn. Diat., p. 7; Bacill., p. 50. 



Valvae disco in partes 2 distincto, exteriori annulari, striis levi- 

 bus vel punctatis, plus minus subtilibus passim hinc inde spinulosis 

 donata, centrali ssepe bullosa, levi vel granulata, granulis sparsis vel 

 radiantibus; frustula e facie connectivali visa recta vel undulata, in 

 fascias non conjuncta. 



1. Cyclotella Pantanelliana Castrac , Anal. micr. di un calc. d. terr. 86 

 di Spoleto, p. 6, Atti Acc. Pont. N. Lincei, XXXVIII, Sess. IV, 



15 .Marzo, 1885. Pantan., I. c, p. 7, — E maximis; a latere re- 

 ctangula, a fronte plana, tertia radii parte circum radiata; area 

 centrali rariusculis margaritis subregulariter radiata, nonnullis pun- 

 ctulis interpolatis. 



In marga pliocenica inferiore agri Spoleiini, Umbriae (Castrac). 

 — Sec. cl. Castracane C. C07ntce (Kuetz.) var. radiosce Grun. 

 similis. 



2. Cyclotella Kuetzingiana Thwait., Ann. Nat. Hist., ser. II, 1848, s? 

 p. 169, t. XI d, i. 1. Sauvage, Ann. Sc. geol., IV, 1873, p. 68. — 

 Frustulis e faeie connectivali visis undulatis, valvis costis margi- 

 nalibus sulitilibus centro subtilissime punctatis, punctis sparsis, gra- 

 nulis 1-3 majusculis solitariis, disco 12-24 a. diam. 



In tripoli niessiniano «Licata» insulae Sicilire (Sauvage). 



Fam. COSCINODISCACEiE 

 Gen. CoscinodiscusEhr.,Kreidethierchen, 1840.Sensu amplo '). 



•; Dc liuius generis speciebns comparanda est Monographia cgrcgii Rattray 

 (A Revision of the genus Coscinodiscus Eiu-b. aud of some allied genera, Edin- 

 burgh, 1890) ubi omnes Co.scimdisci species critice dispositae et descriptae sunt. 



