STAURASTRUM. 65 



respondence between the two algologists that Dr. Liitkemiiller 

 considered all the specimens of so-called St. pilosum he had ex- 

 amined to be without exception either St. hirsutum or St. muri- 

 catum. Thus Dr. Liitkemiiller came to the conclusion that no 

 one knows what St. pilosum Nag. really is, and he was accord- 

 ingly very doubtful about its being a valid species. Whether 

 Professor West agreed with Dr. Liitkemiiller on this point is not 

 certain. A particular alga first identified amongst his records 

 as St. pilosum was later altered to St. Brebissonii, but the date 

 at which the alteration took place is not known. The specimens 

 in question have been examined and they are very similar to 

 PL CXXXVIII, fig. 3. The actual specimen there figured was 

 taken from a collection from Esher West End Common, and 

 identified by Professor West as St. pilosum Nag. Professor West 

 left only one drawing of St. pilosum. and a rough freehand draw- 

 ing of the vertical view. These are reproduced on PI. CXXXVIII, 

 fig. 1. From these and from certain other rough sketches it 

 would seem that Professor West's original idea of St. pilosum was 

 that it should be similar in size to St. hirsutum Breb., but that 

 its semicells should be narrowly elliptical rather than tnmcate- 

 pyramidate as in that species, and its spines should be some- 

 what longer and more delicate. In vertical view the lateral 

 margins are distinctly concave. Liitkemiiller was of the opinion 

 that Nageli's original figure of St. pilosum merely represents 

 a smooth Staurastrum in which the pore threads had hardened 

 and were distinctly visible. 



88. Staurastrum hirsutum (Ehr.) Breb. 

 (PI. CXXXVIII, figs. 4-6.) 



Xanthidium hirsutum Ehr. Org. kl. Rauin. 1834, p. 318 ; Menegh. Svn. 



Desm. 1840, p. 223 : Kiitz. Spec. Alg. 1849, p. 177. 

 Euastrutii hirsutum Kiitz. Phyc. Germ. 1845, p. 137. 

 Staurastrum muricatum Ralfs in Ann. Mag. Nat. Hist. 1845 (in part), t. 11, 



f. 1, a, 6, and c. 

 St. hirsutum (Ehr.) Breb. in Ralfs, Brit. Desm. 1848, p. 127, t. 22, f. 3 ; 



Rabenh. Krypt.-fl. Sachs. 1863, p. 190 ; De Not. Desm. Ital. 1867, p. 50, 



t. 4, f. 41 ; Rabenh. Flor. Europ. Alg. 1868, p. 211 ; Kirchn. Alg. Schles. 



1878, p. 166 ; Wolle, Desm. U. S. 1884, p. 141, t. 45, f. 19-21 (accuracy 



very doubtful) : Cooke, Brit. Desm. 1887, p. 149, t. 52, f. 1 ; Hansg. 



Prodr. Algenfl. Bohmens, 1888, p. 214; De Toni, Syll. Alg. 1889, p. 1165 ; 



Heimerl, Desm. alp. 1891, p. 605 ; West, Alg. W. Ireland, 1892, p. 174 ; 



Alg. Engl. Lake Distr. 1892, p. 19 ; Racib. Desm. Ciast. 1892, p. 389 ; 



Roy & Biss. Scott. Desm. 1893, p. 21 ; West & G. S. West, Alg. S. England, 



1897, p. 494 ; Alga-fl. Yorks. 1902, p. 100 ; Alg. N. Ireland, 1902, p. 48. 

 Phycastrum apkulosiun Ktitz. Spec. Alg. 1849, p. 182. 



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