68 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Var. filiformis. (M. filiformis, Harv., Phyc. Brit., PL 156. — M. Ear- 

 veyana, Nreg. partita.) 



Fronds filiform in outline, axis furnished only at intervals with 

 branches. 



On various alga?, especially Scytosiphon lomentarius. 



Gloucester, Mass., Mrs. Bray. 



Var. filiformis, Penobscot Bay, Maine, Hooper ; Newport, B. I. ; Europe. 



A species forming small tufts on different Phccosporew, probably abundant on our 

 coast, but as yet only recorded in a few localities. Nregeli has shown, 1. c, that the 

 two species of Harvey are merely forms of a single species, the variety filiformis being 

 less fully developed than M. clavceformis, which was first described. 



ECTOCAEPUS, Lyngb. 



(From f/crof, external, and tcupnoc, fruit.) 



Fronds filamentous, monosiphouous or occasionally partly polysi- 

 phonous by radial division of some of the cells; plurilocular sporangia 

 ovate, cylindrical or siliculose, consisting of numerous small cells ar- 

 ranged in regular longitudinal and transverse series; unilocular spo- 

 rangia cylindrical or oval, either stalked or formed by the direct trans- 

 formation of the cells of the branches. 



The genus is here accepted in an extended sense, and includes a number of genera 

 of modern writers which we have preferred to consider subgenera. Perhaps Pylaiella 

 should be kept distinct, as in this subgenus both the unilocular and multilocular 

 sporangia are formed by the direct transformation of some of the cells in the con- 

 tinuity of the filaments rather than in special branches. But in Capsicarpclla we have 

 the multilocular sporangia formed in the continuity of the branches as in Pylaiella, 

 while the unilocular sporangia are partly emergent and seem to be intermediate be- 

 tween those of Pylaiella and Ectocarpus proper. Strebloncma,\i separated from Ecto- 

 carpus by its creeping habit, resembles it perfectly in its fruit, and, as the' different 

 species of Strebloiwma vary considerably as to their procumbent habit, it seems, on the 

 -whole, better not to retain the genus. The described species of Ectocarpus proper are 

 very numerous, but unfortunately they are not well characterized. The greater part of 

 the species may be grouped around E. conferroides and E. fasciculatus as types, but 

 exactly how far differences in ramification and dimensions of the sporangia are to be 

 considered specific rather than mere variations is a matter about which botanists do 

 not agree. One thins is certain, that specific analysis has been carried too far in this 

 group, and it is especially true with regard to the species of Kiitzing. In describing 

 a species of Ectocarpus it is important to have both the unilocular and plurilocular 

 conditions. In most of the species, however, only one form is known. The unilocular 

 sporangia are often difficult to determine, because the Ectocarpi, especially those 

 growing on dirty wharves, are infested by parasites, Chytridium, &c, which produce 

 globular swellings of the cells, which might then, especially in dried specimens, be 

 mistaken for unilocular sporangia. 



Besides the two forms of sporangia, Thuret and Bornet have recorded the existence 

 of bodies to which they have given the name of antheridia. It has been suggested 

 that the antheridia were cells distorted by parasites. We have never seen anthe- 

 ridia in American specimens, and are not in a position to express any opinion. The 

 fact that a conjugation of the zoospores has been observed by Goebel in E. 2>nsil1us 



