62 , EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



As ail account of the families into which the suborder is divided has already been 

 given on pp. 15-17, it is unnecessary to repeat them here, but the reader will find 

 them briefly described in their order on subsequent pages, together with a synopsis 

 of the genera found on our coast belonging to each family. 



Family SCYTOSIPHONE^. 



Fronds unbranching, either membranous or tubular ; plurilocular spo- 

 rangia in short filaments, densely covering the whole surface of tbe 

 fronds ; unilocular sporangia not well known. 



Fronds expanded membranes PJiyllitis. 



Fronds tubular Scytosiplion. 



PHYLLITIS, (Kiitz.) Le Jolis. 

 (From <}>v?,7utt}c, a name given by Dioscorides to an unknown plant.) 



Fronds olive-brown, simple, membranaceous, composed of a cortical 

 layer of minute colored cells and an internal layer of larger, oblong, 

 colorless cells, which are sometimes prolonged downwards in the form 

 of short filaments ; plurilocular sporangia formed from the cortical cells, 

 covering the surface of the fronds, consisting of a few (4-6) cells ar- 

 ranged in short filaments, which are closely packed together at right 

 angles to the surface of the fronds; unilocular sporangia and para- 

 physes unknown ; growth from the base. 



A genus consisting of two species, formerly placed in the genus Laminaria in conse- 

 quence of their membranous habit, but differing essentially from the true Laminaria 

 in the structure and disposition of their sporangia. 



P. fascia, Kiitz. (Laminaria fascia, Ag.) 



Fronds gregarious from a disk-like base, three to six inches long, a 

 quarter to half an inch wide, linear-elongate, contracted at the base 

 Into a short stipe. 



Yar. c^ispitosa. (PJiyllitis ccespitosa, Le Jolis, Eludes Phycol., p. 10, 

 PI. 4. — Laminaria ccespitosa, Ag. — Laminaria fascia, Harv., in Phyc. 

 Brit., PI. 45. — Laminaria debilis, Crouan, Alg. Finist., No. 81.) PL IV, 

 Fig. 3. 



Fronds stipitate, cuneiform, often falcate and undulate. 



Yery common on stones between tide-marks; widely distributed over 

 all parts of the world. 



About the limits of the present species there is a diversity of opinion. Le Jolis 

 regards the L. fascia and L. ccespitosa of Agardh as distinct species, but by Harvey 

 they were considered as merely different forms of the same species. Harvey's opinion 

 s eems to us to be correct, for it is impossible to draw the line between the two forms 

 3,s found on our coast, 



