THE MARINE ALG/E OF NEW ENGLAND. 31 



the gcnns Dolichospermiim ot" Tlnvaiti-s. Kalfs, in Annals and Ma*;, of Nat. History, 

 Vol. V, 2d sorirs (18')0), p. 32.'>, f()llo\vin<; C. A. Agardh, who first dt'scribcd the genus 

 Sphirrozyga (Flora, 11*27), says that iu Sphcrrozyga the spores are tirst formed from tho 

 cells nearest the vesicular cells (heterocysts), as is shown by Professor Wood's figure, 

 PI. 3, Fig. 3. to 1h> the case with tho species from Camden. Neither can wo regard 

 S. CarmUhatlii, Harv., as a synonym of CylindroftprrmHm polyftporum, Kiitz., as given 

 by Profes.sor Wood. Although wo have examined a large number of specimens, in 

 only one instance have we found more than a single spore on each side of the het- 

 eroeyst, which is quite dilTereut from C. polynjyorum, Kiitz. 



XODULARIA, Merteus. 



(From jwdulus, a little joint.) 



Filaments free, trichoma inclosed in a definite sheath, cells discoidal. 

 Heterocysts at regular intervals. Spores numerous, contiguous, not adja- 

 cent to the heterocysts. 



The genus Spermosira of Kutzing is included under the above. 



y. Haevfa'ANA, Thuret, Class, des Nostoch. (S2)ermo8ira Harveyana, 

 Thwaites, Thyc. Brit., Tl. 173r.) 



Filaments curved, cells discoidal, .0013-20 x .004"^°^, heterocysts 

 .0035°^°^ in diameter, spores numerous, about 4rS together, spherical, 

 .005-70™™ in diameter. 



Charles River, Cambridge, Mass. ; Europe. 



Found in small quantities, mixed with Spharrocyga, in comjiauy with lihizoclonium. 



SPIEULINA, Turpin. 

 (From spirula, a small spiral.) 



Filaments simple, without a proper sheath, oscillating, spirally 

 twisted. Spores unknown. 



S. TENUissniA, Kiitz., Phyc. Brit., PI. 105, Fig. 3; Farlow, Li.st of 

 Marine Alga?, 187G. PL I, Fig. 4. 



Filaments intricately interlaced, .0035™™ in diamet-er, hyaline, spiral, 

 closely twisted, cell divisions scarcely visible, oscillations rapid. 



Eastport, Maine ; Gloucester, Cambridge, Wooil's IIoll, 3Iass. ; Europe. 



This species is common at Eastport, where it fonns, mixed with species of Oncil- 

 laria^ dark purple-colored patches on tho wharves at h)w-water mark, and it is with- 

 out doubt to bo found in similar localities along tho whole coast. 



We found at Wood's IIoll, in 1876, a species of Spirulina which formed a greenish 

 fdm on decaying alga? five or six feet below low-water mark, and the same si)ecies was 

 collected by Mr. F. W. Hooper at Key West. It agrees closely with S. Thurttii, Cm., 

 a species which ditTcrs from .S. icnuissima, Kiitz., in having slightly smaller filaments, 

 which are also less tightly coiled. It hardly seems to us, however, as though tho 

 difference was sufficient to separate tho two species. A Spirulina with much finer 

 filaments than in S. tcnuissima, and with a much more open spiral, occurs at Wood's 

 Holl, but we have never found it in sufficient quantity to ascertain tho species. 



