THE EEESHWATEE ALGJ^ OF MADAGASCAR. 43 



Crass, cell, veget. 38-48 ^ ; longitudo diametro 2-4-plo longior ; long, zygosp. 73- 

 75^; lat. zygosp. 40-49 fi. 



No. 18. 



8. Spihogyha, sp. 



Cellulse diametro (32-34-5 n) 5-7-plo longiorcs, extrcmitatibus nmiquam replicatis, 



fasciis spiralibus 2, anfractibus 6-7. 

 No. 5. 



9. Spikogyra, sp. 



Cellulse diametro (13-5 yu) 8-10-plo longiores, extrcmitatibus nunquam replicatis, fasciil 

 spirali, anfractibus 6. 

 No. 1. 



Order DESMIDIACE^. 



Genus Spondylosium, Br6h. 



10. Spondylosium papillosum, nov. sp. (PL IX. fig. 19.) ♦S'. fills tortis, sine vagina, 

 mucosa; cellulae pauUo longiores quam latae, modice constrictae, sinu aperto ct 

 obtuso ; semicellulaB ellipticEe, apicibus truiicatis, lateribus granulis 3 minutissimis 

 instructis, a latere yisse subcirculares. 



Long. cell. = lat. =9 '5 /x; lat. istbm. 5'5 ^; crass. 5 /*. 



No. 3. 



This is nearest to Spondylosium tetragofium, West (Freshw. Alg. of W. Ireland, p. 115, 

 pi. XX. fig. 2), but the cells are much more constricted and have three very minute lateral 

 granules. 



Genus Desmidium, Ag. 



11. Desmidium Swartzii, x\g. Syst. Alg. p. 9 ; Ealfs, Brit. Desm. p. Gl, tab. iv. 

 Var. AMBLYODON, Rabenh. H. Europ. xllg. iii. p. 154. 



Long. ceU. 15-5 ^u ; lat. cell. 30 ^ ; lat. isthm. 25 ^. (PL IX. fig. 35.) 

 No. 0. 

 Var. QUADRANGULATUM, Roy (Scottish Desmids, 1893). {Desmidium quadrangulatum, 

 Ralfs, in Annals of Natural History, vol. xv. p. 405, t. 12. fig. 9 ; Erit. Desm. 



p. 62, tab. V.) 

 Lono-. cell. 17-19 fx ; lat. ad bas. semicell. 32-10 /u ; lat. apic. 30-36 /u ; lat. isthm. 



26 u. Vl- I^- fig- 3^-) 



No. 0. 



The specimens observed of this variety had very rounded angles, as in var. amhlyodon, 

 Uabenh with which it agreed in all characters except the quadrangular vertical view. 



g2 



