34 EEPOET OF COMMISSIONEE OF FISH AND FISHEEIES. 



Wood's Holl, Mass. ; Atlantic shore of Europe. Summer. 



A species easily recognized and probably* common along the New England coast in 

 summer, but rarely found in sufficient quantities to make herbarium specimens. It 

 is usually found in small streaks, so entangled with other NostocMneas and Confervas as 

 to be quite inextricable. At times it is found tolerably pure on the old stalks of Spar- 

 Una, between tide-marks. Pure specimens may be obtained by allowing specimens 

 in which filaments of this species are entangled to remain overnight in a shallow 

 dish of salt water, when the Microcoleus will have freed itself from other substances 

 and come to the surface. As generally found, the plant looks like an attenuated corn- 

 ucopia, owing to the rupture of the sheath iu the middle, allowing the filaments to 

 project. This is shown in Harvey's figure, 1. c, and also in PI. II, Fig. 3, where only 

 half of the plant has been drawn. Normally the sheaths are about a quarter of an 

 inch long, about .075 ra,n broad in the middle, and tapering to about .012 mm at the 

 ends. Color a deep bluish green. The filaments readily escape from their sheath, and 

 might iu this condition pass for a species of Oscillaria. 



Microcoleus terrestris, Desmaz. (Chthonoblaslus rcpens, Kiitz.), and M. versi- 

 color, Thuret, are not infrequently found in muddy places in the interior of .New 

 England. 



LYNGBYA, Ag. 



(Named in honor of Hans Christian Lyngbye, a Danish botanist.) 



Filaments free, each provided with a distinct sheath, simple, destitute 

 of heterocysts, no proper oscillations. Spores unknown. 



L. majuscula, Harv. ; Mermaid's Hair. ( Conferva majuscula, Dillw. — 

 L. crispa, Ag. in part, — L. majuscula, Harv., Phyc. Brit., PI. 62; Ner. Am. 

 Bor., Part III, p. 110, PL 47 a.) PL I, Fig. 4 



Filaments long, forming floating tufts, crisped, about .028 mm to .032 mm 

 in diameter, blackish green, sheath prominent, cells 8 to 10 times as 

 broad as long. 



Cape Cod, Mass., to Key West; Europe; Pacific Ocean. Common 



and widely diffused. Summer. 



The largest, most striking, and most common of our marine Lyngbyw, easily recog- 

 nized by the length and diameter of its filaments and its color, which is a blackish 

 green. It forms during the later summer months large tufts upon Zostera and various 

 other alga?, and is often found floating free in considerable quantities. In the center 

 of the masses the filaments are intricately twisted together, but on the surface they 

 float out from one another, so as to deserve the common name of mermaid's hair. In 

 the older specimens the filaments are very much curled and twisted, forming the L. 

 crispa of some writers. The sheath is always well marked, although, as is the case in 

 all the species, it varies so much in thickness under different circumstances as to render 

 it impossible to give accurate measurements. The heterocysts, " cellulis interstitiali- 

 bus sparsis," described by Eabenhorst in this species, Flora Europ. Alg., Part II, 

 p. 142, have, in reality, no existence. 



L. ^estuarii, Liebm. {L. aeruginosa, Ag. — L. ferruginea, Ag., in Ner. 

 Am. Bor., Part III, p. 102, PL 47 b; Phyc. Brit., PL 311.) 



Filaments forming a verdigris-green stratum, about .01G-18 mm in diam- 

 eter, sheaths distinct. 



