182 welwitsch's afkigan freshwater alg^. 



Var. TROPicuM, var. n. (tab. 3G8, fig. 20). Var. semicellulis plus 

 ventricosis, spiuis miuoribas ot mmierosioribus, in seriebus trans- 

 versis trans angulos, apicibus processuum brevium trideuticulatis. 

 Long. 20 ji ; lat. 27 ji- ; lat. isthm. 8 /x. 



Huilla. In paludibus exsiccandis ; April 18G0. No. 176. 



This may be a proper species, but only one example was met 

 with, and, until further examples are obtained, it had better be 

 regarded as a variety of Schmidle's alpine species. 



21. S. ELEGANTissiMUM Joliuson iu Bull. Tovr. But. Club, xxi. 

 290, t. 211, f. IG (1894). 



Var. REDUCTUM, var. n. Var. paullo minor, processibus brevi- 

 oribus, spinis minoribus, dentibus ad apices processuum multe 

 minoribus, sine annulo spinarum brevium ad basin semicellularum. 

 Long. 30 [J. ; lat. cum proc. 37 /j- ; lat. isthm. 8 /x. 



Libongo. Ad margines flum. Lifune ; Sept. 1858. No. 201. 



22. S. cerastoides, sp. n. (tab. 369, fig. 13). S. subparvum, 

 circiter IJ-plo latins quam longius (cum processibus), leviter con- 

 strictum ad medium ; semicellulfe introrsum lunata? lateribus 

 ventralibus late tumidis, extremitatibus in processus breves at- 

 tenuates inliexos productis, per marginem dorsalem totum aculeis 

 brevibus 11 (circ.) supra verrucas parvas (verrucis infra marginem) 

 regulariter dispositis, apicibus processuum leviter recurvatis et tri- 

 denticulatis, marginibus iuferioribus processuum et semicellularum 

 glabris, serie transversa verrucarum denticulatarum trans semi- 

 cellulas et secundum processus, seriebus annularibus duabus 

 granulorum minutorum ad basin semicellularum ; a vertice viss 

 late fusiformes, verrucis emarginatis utrobique sensim et sensim 

 dimiuutis polos denticulatos versus, etiam serie aculeorum mi- 

 nutorum intra marginem uuumquemque de polo ad polum. Long, 

 sine spin. 31'5-36-5 //, cum spin. 38-39 /x; lat. (cum proc.) 48-50 /x; 

 lat. isthm. 13-15 ji; crass. 18 /x. 



Huilla. In uliginosis editioribus prope Humpata, Empalanca 

 et Lopollo, plagas spongiosas unacum Eriocauloneis, Xyridibus et 

 Utriculariis constituens ; May 1860. No. 15. Etiam in paludibus 

 exsiccandis ; April 1860, No. 176. 



This species possesses in common with its nearest ally S. Cerastes 

 Lund, a smooth under surface to the processes which have a faintly 

 recurved apex, as well as a double series of warts along each side. 

 The character and arrangement of these warts, however, its less 

 incurved processes, the different form of its semicells, together with 

 the constantly fusiform vertical view, readily distinguish it. 



23. S, GRACiLE Ealfs in Auii. Xat. Hist. xv. 155-6, t. xi. f, 3 

 (1845); Brit. Desm. 136, t. xxii. f. 12 (1848). 



Var. CYATHIFORME West & G. S. West in Trans. Linn. Soc. 

 ser, 2, V. 77, t. ix. f. 2 (1895). Long. 52 /j. ; lat. (c, proc.) 82 fx ; 

 lat. isthm. 15 /x. 



Pungo Andongo. In stagnis prope Anbilla (Condo) ; March 

 1857. No. 177. 



Var. pusiLLUM West & G. 8. West, I. c. f. 4, Long, 25 /a ; lat. 

 (c. proc) 34 //; lat, isthm. 7*5 //. 



