110 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. 



Suborder PORPHYRE^E. 



Fronds brownish purple, composed of cells imbedded in a gelatinous 

 net-work, arranged in filaments or in membranes formed of a single 

 layer of cells ; spores formed by the division of a mother-cell into eight 

 cells, arranged by fours in two layers ; antherozoids spherical, color- 

 less, destitute of proper motion, formed by division of a mother-cell into 

 32-64 parts. 



The present suborder comprises the genera Porpliyra and Bangia, and perhaps also 

 Erythrotrichia and Gonioirichum. In Porpliyra the frond consists of a single layer of cells, 

 of which those near the base send downwards root-like appendages, by means of which 

 the fronds are attached to the substratum. The spores are formed at the marginal 

 portion of the frond by the division of the vegetative cells, at first into two cells by a 

 vertical partition, and the subsequent division of the two cells into four by cruciate 

 partitions. Thus, when mature and seen from above, the eight spores seem to be 

 arranged in two superimposed series of four. The spores escape by the dissolution of 

 the outer part of the frond, leaving behind the empty gelatinous net-work. When 

 free they are found to consist of protoplasm without a cellulose wall, and they move 

 about for a short time with an amoeboid motion. The antherozoids are also formed 

 by the division of the vegetative cells, but the division is carried farther than in the 

 production of the spores, for, in addition to the vertical and cruciate partitions de- 

 scribed in the latter case, a second vertical and cruciate division takes place, so that 

 the original vegetative cell is divided into 32-64 cells. Janczewski applies the name 

 antheridium to the collective mass of antherozoids formed from a single vegetative cell. 

 As the division takes place the antherozoids lose their color. When mature they are 

 spherical and escape in a manner similar to that of the spores. Bornet and Janczewski 

 state that the antherozoids are destitute of any proper motion, and we can confirm 



fronds are distorted by parasites, which produce deformities like those described by 

 Reinsch as due to species of Choreocolax. Such distortions axe perhaps most frequently 

 found on Cystoclonium purpurascens. In our present ignorance of the fructification, 

 specific identification is out of the question, and, in this connection, it is only necessary 

 to quote the generic descriptions of Reinsch, 1. c, with an eniimeration of the species 

 attributed to our coast : 



CHOREOCOLAX. True vegetable parasites; fronds consisting of two portions, one 

 of which extends through the tissue of the infected plant, the other of which swells 

 above the surface of the infected plant, forming a convex mass, which is hemispherical 

 or spherical, semi-ellipsoidal or irregular in outline ; the cells which are contained iu 

 the infected plant either more slender than the others or of the same shape, cells of ex- 

 ternal portion equal or unequal, arranged Avithout order in densely intricate subramose 

 threads, terminal cells sometimes longer and more slender ; fructification ? ; polysporan- 

 gia? 



C. Rabenhorsti. On Delesseria sinuosa, Anticosti ; Gloucester, Mass. 



C. polysiphonijs. On P. fastigiata, Atlantic shore of North America. 



C. mieabilis. On Ehodomela subfusca, Atlantic shore of North America. 



C. Americajstus. On Loplmra Royana, &c, Atlantic shore of North America. 



C. tumidus. On Ceramimn involutttm, West Gloucester, Mass. 



PSEUDOBLASTE. False vegetable parasites ; frond convex, more or less regular in 

 outline, formed of similarly shaped cells, generally arranged in longitudinal series, 

 arising from a densely appressed base (the cells without any organic connection with 

 the cells of the infected plant) ; propagation ? 



P. irregularis. On Lopliura Royana, Atlantic coast of North America. 



