916 Conjugatse, Desmidiaceae, Xanthidium. 



risia 1888, p. 402, Cosmarhim Balfsii Mask. N. Z. D. p. 316, 

 t. 12, f. 30? — Maxima, diametro 1 ^j^-V^o longior, medio pro- 

 funde constricta, iucisura sublineari angusta (extremo ampliata); 

 semiceilulis (circulari-pyramidalibus) e basi recta fere ad medium 

 ?equali latitudine lateribus subrectis, ab hoc loco vel sa^pe ad an- 

 gulos inferiores sensim angustis iateribus convexis apice rotundatis 

 vel vulgo medio apice truncatis vel nonnumquam subretusis angulis 

 inferioribus subrectis obtusis; a vertice visis late ellipticis, a latere 

 latissime ellipticis; meinbrana crassa distiucte dense punctata;py- 

 renoidibus binis ; laminis chioroplijllaceis senis (ut in Cosm. can- 

 diano Delp.). 



Hab. ad cc Waimakariri river, Arthur Pass, Lake Lyndon, Tere- 

 makau et Arakura, Orakeikorako » in Nova Zelandia (S. Berggren). 

 — Magnitudiue ab omnibus speciebus confinibus differt, pneterea a 

 Cosmario pachydenno (Lundell) longitudine majore et semicel- 

 lulis apicera versus magis attenuatis; a Cosmario pyramidato 

 (Breb.) lateribus magis convexis, membrana crassiore dissimiliter 

 punctata, a Pleurofceniopside Cacumi dispositione massae chloro- 

 phyllacefe etc. — Dimens. 144-168, 98-110, lat. isthmi 46-56 [j.., 

 crass. 71-75 jj.., crass. merabr. ad 8 [j.. 



XANTHIDIUM Ebrenb. [1833] Abhand. Berl. Akad. p. 317 (Etym. 

 .r«n//zos fnlvus), Rabenh. Fl. Eur. Algar. III, p. 221, Kirchn. Alg. 

 Schles. p. 154, Wolle Desm. U. S. p. 92, Cooke Brit. Desm. p. 129, 

 Hansg. Prodr. p. 191!, De-Toui e Levi Fl. Alg. Ven. III, p. 52.' 

 Zygoxanihium Ehrenb. [1840] Ber. Akad. Berl. p. 218. — Cellulse 

 singuLne vel geminfe concatenatas, inflato-rotundata?, profunde con- 

 strictae, ambitu rotundatae, oblongaB vel angulata^, apice non eraargi- 

 natae nec incisa), superficie aculeis validis vel prominentiis (apice 

 fissis) 2-ies 8 iustructai; e vertice visa3 rotundataj vel oblongie, 

 ssepe medio ventricoso-tumidae; semicellulae compressEe, obloug^, he- 

 mispha^ricffi vel subquadrangulares, centro in tuberculum rotunda- 

 tura vel truncatum et denticulatum protuberantes, ex transverso 

 oblongo-rotundatcc; chlorophora laminreformia, parietalia. 

 Generatio zygotis globosis, aculeis instructis vel carentibus. 



SeoHo 1. Schlzacanthium Lund.: Acuiei cellularum apice flssi; zygota exaculeata. 



1. Xanthidium armatum Breb. in Ralfs Brit. Desmid. p. 112, t. XVIII, 



Liste p. 134, n. 1, Desmaz. Cr. de Fn ed. II, n. 1358, Rabcnh! 



