Bacillariese, Achnanthaceae, Achnanthes. 469 



coneis? excenirica Donk. in Micr. Journ. VI, p. 25, t. 3, f. 11, 

 Pritch. Inf. p. 871, t. 7, f. 10, Rabenh. Fl. Eur. Algar. I, p. 104, 

 Sm. Sp. T. n. 71 Excentron et Anorthoneis cancroides auct. — 

 Frustulis libere vigentibus; valvis suborbicularibus, 25-50 p.. 

 diam., late marginatis, rhaphe excentrica, recta ; striis punctatis, 

 convergentibus. 



Hab. ad oras Anglise, hic illic, abundanter (Donkin). 



Pamilia VI. Achnanthaceae (Kuetz.) Grun. 



Achnanthacew Kuetz. [1844] Bacill. p. 70, 74, em. Grun. [1860] in Wien. Ver- 

 handl. X, p. 511 et [186^] XII, p. 430, De-Toni [1890] Osserv. tass. Bacill. 

 p. 900. 



Valvse secus axin longitudinalem symmetricte, secus axin transver- 

 salem tum symmetricse tum asjmmetricse, costis transversis vel striis 

 transversis punctatis donatse, inasquales, concava rhaphe noduloque 

 centrali (stauro?) instructa, convexa vero nodulo centrali carens ; cel- 

 lulae (frustula) incurvse ita ut axis transversalis culmen occupet. 



Zonse connectivales secus axin longitudinalem asymmetricas, secus 

 axin transversalem tum symmetricse, tum asymmetricre. 



Phseophora laminseformia (subinde grauuliformia), singula, plerum- 

 que valvae convexae adposita. 



Gonspectus generum 



Achnanthes Bory. — Valvse lineares vel ellipticse (plerumque stipitatae), rhaphe 



recta. 

 Achnanthiclium (Kuetz.) Grun. — Valvae liberae Achnanthidis sed rhaphe 



sigmatoidea. 

 [Monogramma Ehr. — Frustula Achnanthidis in una alterave valvarum linea 



media transversali instructa. (Vix ab Achnanthide distinguendum)]. 



ACHNANTHES Bory [1822] Dict. class. I, p. 79, 593, Ag. Syst. Alg. 

 p. XIII (Etym. achne puncta et anthos flos), Kuetz. Sp. pag. 54, 

 Rabenh. Fl. Eur. Algar. I, p. 309, Grun. et Cl. Arct. Diat. p. 18, 

 V. H. Syn. p. 128, Brun Diat. Alp. Jura p. 28, De-Toui Osserv. 

 Tasson. Bacill. p. 900, Cymhosira Kuetz. [1844] Bacill. p. 77, Sp. 

 p. 57 , Achnanthella Gaill. mscr. teste Lemaire [1841] in Orb. Dict. 

 class. 1, p. 73, Con/ervce, Diaiomatis, Echinellce, Fragilarioe, Mo- 

 nogrammatis, Slauroneidis,Achnanihidii, Cocconeidis, Odonfidii, 

 Falcaiellce, Synedrce sp. auct. nonnull. — Valvse naviculacea?, dis- 

 similes, rhaphe recta donatse, una (superior) tantum pseudorhaphen 

 sine nodulis ostendens, altera (inferior) rhaphen genuinam nodu- 



