122 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Common from New York northward ; California; Europe. 



A common species, especially frequenting the under surface of rocks and stones near 

 low-water mark. It has not yet beeu found with us in fruit, but Californian speci- 

 mens bear tetraspores. In Europe the time of fructification is the spring, and tho 

 species should be examined at that season on our own coast. Harvey states that tho 

 tetraspores are tripartite, but other writers — as Thuret, Agardh, and Nyegeli — agree 

 in asserting that they are cruciate. In Californiau specimens the formation of the 

 tetraspores is somewhat irregular, and although in most cases the cruciate division is 

 plain enough, in others it seems to be rather tripartite. 



Subgenus ANTITHAMNION, Thuret. 



Branches opposite or whorled, without cortication ; tetraspores cru- 

 ciate. 



C. cruciattjm, Ag. {Antithamnion cruciatum, Nseg. — C. cruciatiim, 

 Phyc. Brit., PI. 1G4.) 



Fronds tufted, one or two inches high, main branches sparingly and 

 irregularly branched, secondary branches short, borne in twos or fours 

 just below the nodes, always regularly opposite, and when in twos the 

 succeeding pairs at right angles to one another, below subdistant, at 

 the apex densely approximate and corymbose, pinnate with erect, alter- 

 nate, distichous branchlets; tetraspores cruciate, sessile, or shortly 

 stalked at the base of the secondary branches. 



On wharves at low- water mark and on alga? in shallow water. 



Bed Hook, N. Y., Harvey; Orient, L. I.; Noank, Conn.; Wood's Holl 



and several localities in Vineyard Sound, TV. G. F.; Europe. 



Not common, but, on the other hand, not rare south of Cape Cod. It is a small and 

 not very beautiful species when growing, but rather pretty when pressed. It is dis- 

 tinguished from the following species by its small size and sparingly branched main 

 branches and by its tetrastichous, not distichous, secondary branches, which are 

 densely approximate .at the tips, so that in dried specimens the plant is rather pale 

 except at the tips. Cystocarps and antheridia have never been found on our coast. 

 Crouan states that the cystocarps, which are rare, are large, rounded, and slightly 

 lobed. The branches of the present species, as well on our own shore as in Europe-, 

 are beset with small cysts with oily contents — the Chylridium plumulce of Cohn. Tho 

 same parasite is also found on the branches of C. Pylaiswi and C. plumula on the New 

 England coast. 



C. floccosum, Ag. (C. floccosum, Phyc. Brit, PI. 81. — Pterotham- 

 nion floccosum, Nseg.) 



Fronds three to six inches long, capillary, main branches irregularly 

 and sparingly branched below, above with numerous alternate branches, 

 which give the tips of the frond a rhombic-ovoid outline, clothed through- 

 out with short, simple, opposite, distichous, subulate, secondary branches ; 

 tetraspores cruciate, sessile or on short stalks on the lower part of the 

 secondary branches. 



