128 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Fronds giobosely tufted, one to three inches high, filaments very del- 

 icate, slightly corticated at base, main branches many times divided? 

 secondary branches long and flexuous, pinnate with numerous pinnately 

 compound branchlets 5 antheridia sessile in tufts at the nodes of the 

 branchlets j tetraspores tripartite, sessile on the upper side of branchlets ; 

 favell?e binate on the upper branches. 



Yar. UNiLATERALE, Harv. 



Fronds small and very delicate, branches and branchlets often secund. 



Yar. FASTIGIATUM, Harv^ 



Branches fastigiate, the lesser ones densely ramulose at the tips. 



Yar. AYaltersii, Harv. 



Upper branches distichously compound-pinnate, branchlets patent. 



On Zostera and diiferent algic. 



Common in Long Island Sound ; Gloucester, Mass. 



The forms wliicli have been referred on our coast to C. hyssoideum and C. corym- 

 hosum are hopelessly confused. Although as described by algologists the two spe- 

 cies are sufficiently distinct, in practice it is difficult to say where one begins and 

 the other ends. According to the books, the ramification of the upper branches is 

 dichotomous in C. coryiribosum, whereas it is always alternately pinnate in C. hyssoideum. 

 In some of the forms of the last-named species, however, the tips are corymbose and 

 the cells of the axis are short and zigzag to such a degree that the tips at least appear 

 to be dichotomous. Of the tw^o species in question, C. corymhosum is the less delicate 

 and gelatinous, and is not so decidedly rose colored as C. hys8oideum,\)nt, as far as our 

 present information goes, although in its typical form C. hyssoideum is not only com- 

 mon — apparently more common than in Europe — but also easily recognizable, its ex- 

 treme forms are not sufficiently well known. The Kiitzingian method would be to 

 split the species up into four or five new species. According to Crouan and Bornet, 

 this species has seirospores. 



C. CORYMBOSUM, (Engl. Bot.) Lyngb. (C. corymlyosunij Phyc. Brit., PI. 

 272 5 Etudes Phycol., Pis. 32-35. — Pcecilothammion corymhosum, ^seg.) 



Fronds tufted, two to three inches high j filaments very delicate, cor- 

 tications wanting except at base, main branches several times pinnately 

 or irregularly divided, secondary branches pinnate with dichotomously- 

 multifid, fastigiate branches which end in hyaline hairs j tetraspores 

 tripartite sessile at the nodes of the branchlets, occupying the place of 

 an ultimate branchlet j antheridia in tufts, sessile on the upper inter- 

 nodes ; favellse binate on the upper part of the branches. 



Yar. SECUNDATUM, Harv. 



Lesser branches frequently secund, ultimate branchlets irregular, 

 scarcely corymbose. 



On Zostera. 



Halifax, Boston Bay, New London, Providence, Harvey. The var. 

 secundatumj Massachusetts Bay, Greenport, Harvey. 



