THE MARINE ALG^E OF NEW ENGLAND. 33 



O. limosa, Kiitz., var. chalybea, Tab. Phyc, Vol. I, PI. 41, Fig. 3 ; 

 Le Jolis, Liste des Algues Marines. 



Filaments .O0S-9 mm in diameter, flexuous, apex obtuse, oscillations 

 marked, cells about lialf as long as broad, purplish colored. 



Eastport, Maine; Europe. 



Forming a slimy layer on piles. Our specimens seem to agree well with specimens 

 from Cherbourg. 0. UttoraUs, Harv., of Crouan's Alg. Finistere, No. 325, is apparently 

 very near to this, if not the same. 



O. subtjliformis, Harv., Phyc. Brit., PI. 251 b. 



Filaments .008-7£™ m in diameter, at the end tapering to an incurved 

 point, cells about one-third as long as broad, bluish green. 



Charles River, Cambridge ; Europe. 



O. subtorulosa, (Breb.). (Phormidium sitbtoriilosum, Breb., in Kiitz. 

 Tab. Phyc, Vol. I, PI. 49, Fig. 5.) 



Filaments .003-4 mm , cells nearly cuboidal, with rounded angles, so 

 that the filament appears slightly crenate. 



Eastport, Maine; Wood's Holl, Mass.; Europe. 



To this species is doubtfully referred a form common on wharves at Eastport 

 and on the government wharf at Wood's Holl, where it forms slimy patches, mixed 

 with Spirulina, &c. The filaments of this species bear a decided resemblance to the 

 trichomata of Microcoleus chtkonoplastes, and it may perhaps be a question whether 

 they are not really a stage of that species in which the trichomata have escaped from 

 the enveloping sheath. Opposed to this view is the large quantity of filaments and 

 apparently an entire absence of empty sheaths. That the trichomata of M. chthono- 

 2>lastes often escape from the sheath can easily be seen, but how long they remain fre<j 

 and how rapidly they increase under such circumstances is uncertain. 



MICROCOLEUS, Desmaz. 



(From fiiKpog, small, and Kolcog, a sheath.) 



Filaments slowly oscillating, destitute of heterocysts, several uuited 

 in a single gelatinous sheath, which is either simple or branching. 



M. chthonoplastes, Thuret. ( Oscillatoria chthonoplastes, Lyngbye — 

 Chthonoblastus Lyngbei, Kiitz. — Microcoleus anguiformis, Harv., Phyc. 

 Brit., PI. 249; Kiitz., Tab. Phyc, Vol. I, PI. 57.— Chthonoblastus angui- 

 formis, Rab., Flora Europ. Alg., Sect. II, p. 133.) PI. II, Fig. 3. 



Sheaths elongated, fusiform, being six or more times broader in the 

 center than at the extremities, simple, several twisted together so as to 

 form a green stratum, filaments dark green, about .005 mm in diameter, 

 intricately twisted together, three or four only at the extremity of the 

 sheath, but very numerous at the center, where the sheath is frequently 

 ruptured, allowing the filaments to protrude ; cells as long as broad, or 

 a little broader, terminal cell acutely pointed. 

 S. Miss. 59 3 



