Acta Societatis pro Fauna et Flora Fennica, 49, N:o 7. 53 



X. antilopaeum, especially „forma" Nordstedt, Alg. Brasil. 

 (1877) page 26 fig. xyl. 5. Nevertheless our form with its, 

 most commonly, six pairs of spines is apparently nearest 

 to X. fasciculatum and is in my opinion best placed here. 

 It is most probable that this variety with equal justice 

 could be separated as a distinct species. A central spine 

 (as in X. antil. v. canadense) was observed once. 



Hab. Raisala (SE). — PI. 4 fig. 25- 27. 



X. cristatum Breb. A form of var. uncinatum Breb. 

 with an accessory spine at each apical angle was observed. 

 (PI. 4 fig. 36). [N:o 824]. Likewise f. polonica G u t w. was 

 observed with some small accessory spines above each 

 basal angle. (PI. 4 fig. 37). [N:o 1117]. 



var. dimazum Gronbl., Desm. Keur. Semicellulae 

 8-angulato-ellipticae in area centrali papillis binis glabris 

 ornatae, ceterum membrana glabra subtiliter porosa. Cum 

 spin. long. 61, lat. 57; sine spin, long 49, lat. 44, isthm. 15, 

 crass 32 fi. [N:o 958]. — This variety is particularly notice- 

 able as being analogous to the var. dimazum of X. antilopeum. 



Hab. Messukyla (W). — PI. 3 fig. 47—48. 



var. uncinatum Breb. f. longispina nova f. Semicellulae 

 truncato-pyramidatae angulis rotundatis, lateribus retusis 

 convergentibus (ut in Ralfs, Br. D. pi. 19 f. 3d, 3e); sinu 

 aperto introrsum rotundato. Membrana glabra, subtiliter 

 porosa, in area centrali incrassata fusco-lutea. Cum. spin, 

 long. 87, lat. 80, sine spin. long. 62, lat. 47, long, spinae 

 ad 19, isthm. 13 fi. [N:o 803]. — The basal spines are 

 sometimes very small or even totally absent. The central 

 area is always smooth. Compare Borge, Siissw. Chlor. 

 Archang. pi. 2 f. 14. 



Hab. Gov. of Archangel. — PI. 3 fig. 46. 



Forma ad X. mayori West (Columb. 1914 pi. 22 f. 41) 

 valde accedens. Spinis basalibus singulis, mediis ternis 

 (vel geminatis), superioribus geminatis, praeterea infra apicem 

 spinis singulis. Membrana in area centrali incrassata fusco- 

 lutea protuberantiis binis parvis glabris. Cum. spin. long. 76, 

 lat. 72, crass. 34, isthm. 15 (jl. [N:o 607], — ■ Only one cell 



