THE MAIIIXi: ALG.E OF NEW ENGLAND. 11 



have shown to be eiTonoous views with re^jfanl to the stnietiue and de- 

 veU)pment of the ditt'erent species, and Harvey's three chisses no longer 

 serve as a basis lor ehissiheation. Tlie Mclanospermva' and Chloro- 

 ^innnea' are entirely rearranged, ami although ilrn lihodosjyer mac are still 

 considered to form a natural group, the older name, Floridccv, employed 

 by Agardh, is used to designate them. The l>asis of elassifieation is the 

 structure of the fruit antl the organs of fructilication, in the knowledge of 

 which a great advance has been made during the last twenty years. 



Cm r TOPiiYCE.E. — The lowest of all the algie are those which belong to 

 the order Cryptophycav^ in which, as yet, the only reproduction known is 

 by means of non-sexual si)ores and hormogonia. Most of the species of 

 I he order are bluish green, but some are puri)lish, brown, or even pink, 

 riie bluish-green coloring matter is due to the presence of phycochrome, 

 which is a mixture of chlorophyl and phycocyanin. The last is extracted 

 by water when the algte containing it are bruised, the chlorophyl being- 

 soluble in alcohol. The species of Cniptophijcc(v consist of cells which are 

 usually roundish, or disk-shaped, and which are generally held together 

 by a mass of gelatinous substance which surrounds them. The order 

 is divided into two suborders, according to the arrangement of the cells 

 in relation to the jelly. The lirst suborder, the Chroococcacccc, includes 

 all the species in which the cells are either isolated or arranged in amor- 

 phous or more or less spherical masses. Some of the species of this 

 suborder are very small, and in some of the modern classifications are 

 placed with the Bacteria^ in the order Protophytes, The mode of growth 

 of the Chroococcacew is by division of the cells, first into two, then into 

 four, and so on. The masses which they form may bo called colonies, 

 each cell forming a distinct individual, which is usually capable of living 

 apart from its fellows. Spores, which are known in only one species, are 

 formed by some of the cells enlarging and taking on a thick cell-wall. 

 Nothing like sexual reproduction is seen either in this or the next sub- 

 order. 



XosTOCUiNE.E. — In the second suborder of the Cryptophijcecv^ the Xos- 

 tochineo'j the cells are always attached to one another in the form of fila- 

 ments, to which the name of trichomatn is given. The triclnjinata may 

 either be free, as in OsciUaria (Tl. I, fig. 5), inclosed in a sheath, as in 

 Lynyhya (PI. I, fig. 4), or i)acked in a dense mass of jelly, as in Rivu- 

 laria (IM. II, fig. 1*). The cells composing the trichomata are usually 

 disk-shaped or cylindrical, but are sometimes nearly spherical. 



Besides the ordinary cells, we find in many species a second kind of 

 cell, distinguished from the others by its glassy appearance and its yel- 

 lowish or brownish rather than bluish-green color. (1*1. I, fig. 3, a\ 

 fig. G, h ; PI. II, figs. 1 and 2, a.) They are called hctcrocysts^ and are 

 found sometimes scattered amongst the other cells, and sometimes at the 

 end of the trichomata. their i)osition often serving as a generic character. 

 The reproduction of the Xostochinecv takes place in two ways, ])y hormo- 



