33 ARCHER, ON CLOSTEHIUM ACICULARE. 



coverei's) . As M. de Brebisson has not appended any measure- 

 ment to his description of C. pr(slongum, I may here take 

 the opportunity to give those of my specimens, as follows : — 

 length of frond ,',_,, greatest breadth -r-/--,^ of an inch. It will 

 thus be seen that this species is absolutely (microscopically 

 speaking, by something considerable) the longest Closterium 

 known. Mr. West gives the length of his C. acicidare as -\, 

 of an inch — none of my specimens, which I have little doubt 

 are referable to this species, measured greater than --'^ of an 

 inch, and the greatest breadth was somewhat more than that 

 of his, — ,y ,n, of an inch. The very great length of the frond 

 in C. j)T(dongvin and C. aciculare, combined with the propor- 

 tionately slight width, seems indeed at first to justify a com- 

 parison between those species ; but, as I indicated above, I 

 do not conceive there is any closer affinity between them — in 

 fact, a priori, I should venture to say that C. acicidare, as 

 indicated by its long, slender, setaceous hyaline extremities, 

 when possibly hereafter discovered in a conjugated state, may 

 be found to belong to Kiitzing's genus Stauroceras, that is, 

 in other words, to have a cruciately four-lobed or sub-cruci- 

 form sporangium, while I should as equally predicate of the 

 other an orbicular or elliptic one. I wrote (or intended to 

 write) C j\Iic. Journ.,' 1. c.) of C. jjrcBloiiffum (Breb,), that 

 " in that species the ends are slightly turned upwards, in 

 that respect like C. turfiidum ;" whereas the printer, by placing 

 the semicolon after "upwards," in place of after "C.turgidum," 

 where there should be a comma only, makes me to convey that 

 in the new form ( C. aciculare) the ends look rather downwards 

 (which is the case), ^'iu that respect like C. turgidum" — in 

 which latter, as above indicated, and as is well known, the 

 ends are really turned upw^ards, and not downwards — thus 

 rendering the sentence not only obscure, but absolutely wrong 

 and erroneous. 



Had I seen, when I had the pleasui'e to w rite Mr. West 

 on the subject, either his plate or a specimen, I should 

 hardly have been disjiosed to institute a comparison between 

 his new species and C. macilentum (Breb.), fiu'ther than that 

 like C. pralonguni they are slender forms, and all three 

 non-striate. Since then I have met with, on Plowth, near 

 this city, and in a conjugated condition, a Cfosterimn, which 

 I am disposed to look upon as a small form of C. macilentum 

 (Breb.) ; but on submitting specimens to ]M. de Brebisson, 

 he did not seem quite to concur with me, and obligingly sent 

 me dried authentic specimens of his C. macilentum for com- 

 parison. I must own, however, except that my specimens 

 are slightly smaller in every way, I am not able to see any 



