40 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



stalks upon "which they are growing. It first appears as solid green spots npon the 

 Fucus, which soon swell out into thin bladders, which partly collapse on being 

 removed from the water. The peculiar inverted V-shaped filaments are seen to greater 

 advantage by dissecting with needles small pieces of the frond than by making sec- 

 tions with a razor. 



The only other species of this genus is Rormactis Balani, Thuret, which grows on 

 barnacles on the coast of France. It is a comparatively minute plant, much less 

 striking than our own species, which seems rather to replace, on our coast, the Eivu- 

 laria niiida, Ag., of the coast of Europe, which it resembles in general appearance 

 and habit. The external resemblauce to that species is so great that specimens were 

 sent to Dr. Bornet as B. nitida, Ag. (?) By him it was recognized as a new species 

 of Hormactis, H. Farlowii, under which name it was distributed in Alg. Am. Bor. 

 Since then Dr. Bornet has recognized its identity with Rivularia Quoyi, Ag., of the 

 Marianne Islands. It is not a little remarkable that the species is only known in two 

 localities so widely remote from one another. 



Stigoxema mamillosum, Ag., occurs in a brook which empties into the sea at 

 Rate's Chasm, Magnolia Cove, in Gloucester ; and Calothrix parietixa, Thuret, is 

 found in Nobska Pond, close to the sea, at Wood's Holl. The species named all belong 

 in the present order, but are not strictly marine. 



Order ZOOSPORES. 



Algae either green or olive-brown, in color. Reproduction by means of 



zoospores, which unite in pairs to form a zygospore. 



This order includes all the marine Clorospermece attributed to New England in the 

 Nereis Am. Bor., with the exception of the genus Vaucheria, as well as the greater 

 part of the olive-brown sea-weeds, with the exception of the rock-weeds or Fucacece. 

 The account of the order given in the introduction to the xiresent article should be 

 consulted in the present connection. 



a. Green algae, multicellular, zoospores of two kinds — macrozoospores 



with four and microzoospores with two terminal cilia . . Ghlorosporete. 



b. Green algae, frond unicellular, branching Bryopsidece. 



c. Green algae, froud unicellular, simple Botrydiece. 



d. Olive-brown algae, zoospores of one kind, with two cilia laterally 



attached Phwosporece. 



Suborder CHLOROSPORE^E. 



1. Fronds membranaceous ( Ulvce) 2 



Fronds filamentous 3 



2. Cells in a single layer MonostrQma. 



Cells in two layers JJlva. 



3. Some of the cells furnished with long hyaline hairs Bulbocoleon. 



Cells destitute of hyaline hairs 4 



4. Filaments branching throughout Gladopliora. 



Filaments with short, root-like branches only Bhizoclonium. 



Filaments unbranched 5 



5. Filaments rigid, setaceous Ghcetomorpha. 



Filaments soft and flaccid Ulothrix. 



