Till-: MAKINI-: ALG.E OF NEW KNGLANH. 37 



easily (listinj^nished niulor the microscope, C. confirvicola bcinj; «larkt'r colored, tho 

 filaments thicker, ami only funii.slied with hcterocysts at tho base, wherejw iu 

 C. Crustacea the heterocysts are scattered throiij^h the filann'iit, often solitary, but 

 sometimes as many as eight together, and fretiuently truncate. C. crustacva is also 

 common on n»iUs. 



b. Spociis loriiiiii^- expansions. 



C. SCOriLOKUM, Au\, IMiyc. Brit., PI. 58 h; Xer. Am. IJur., Part 

 III, p. 105. 



Filaments forming strata of indelinito extent, tlcxuous, nsually 

 bran('liin«r, .008-112""" in dianu'ter, hcterocysts l)asal and inlcrcalary, 

 ^licaths thick, striate. 



Var. VIVIPARA. {C. virip<(r(tj llarv., Nor. Am. Jior., Part III, p. lOG.) 



Xaliaut, Wood's lloll, Mass., IT. G. F. ; Ivhode Island, Bailey; Eu- 

 rope. Var. vii'ipara at Xabant, W. G. F., and Seacounet Point, Bailey, 



Forming indefinite-shaped jjatches on rocks, on lihizoclotiium, and other prostrate 

 alga?. Apparently much less common than tho two preceding species. It differs 

 from C. cntntacea in the llexuous habit of tho filaments, which are loosely twisted 

 aronnd one another, in the ninch rarer occurrence of intercalary heterocysts, and iu 

 the color of the lilamcnts, which is not a bright green, but generally brownish. Tho 

 sheaths, too, become thick, dark, and striated. As is the case in all species of Calo- 

 thrix where the fdaments are closely interwoven, the diameter of the filaments is 

 greater and that of the sheath less, proceeding from within outwards. The variety 

 vivipara is only a luxuriant form of tho typical species. 



C. PULYINATA, Ag. (C. hydnoidcs^ Harv.) 



Filaments denseU' packed, forming- a dark ^reen spongy layer, united 

 at the surface iu tooth-like masses, flexuous, .OOG""™ to .0115'""^ in diam- 

 eter, heterocysts intercalary. 



Exs. — Aljj. Am. Bor., Farlow, Anderson & Eaton, No. 50. 



Wood's IIoll, on Avharves. Common. Europe. 



In this species the filaments are much more densely interwoven and flexuous than 

 iu any of tho preceding species. It forms patches looking like a honeycomb, or like 

 .1 small Uifdnum, and can be torn from its attachment in pieces of considerable size. 



C. PAKASITICA, Thuret. {Rivularia, Chauvin. — Sch izosiphon, Lo Jolis.) 

 Filaments loosely united, forming a velvety film, bulbous at base, 



simple or only slightly branching, about .008-10"'"' in diameter, 



heterocysts ba.sal, obliquely truncate. 

 On Nemalion multifidum^ Newport, R. I.; Europe. 



Easily recogni/x'd by its bulbous base and obliquely truncate heterocysts, and its 

 l>eculiar habitat. 



KIVULARIA, Roth. 



(XauK-d from the fluviatilo habitat of mauy of the species.) 



Frond gelatinous, more or less globose, fdaments radiating, atten- 

 uated, funiished with distinct sheaths, branching, a hetcrocyst at the 

 base of each branch. 



