16 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



fascia, which were placed among the Laminarice in the Nereis Am.-Bor. 

 In Phyllitis the frond is membranous, and its whole surface is covered by 

 the plurilocular sporangia which are formed from the superficial cells, 

 which divide so as to form club-shaped filaments consisting of five or six 

 cells, each one of which contains a zoospore. Scytosiphon resembles 

 Phyllitis except that the frond, instead of being a flat membrane, is a 

 hollow tube. There are no paraphyses in Phyllitis, but in Scytosiphon 

 there are ovoidal cells interspersed among the plurilocular sporangia, 

 which seem to be of the nature of paraphyses. No true unilocular spo- 

 rangia are known in this family. 



PuNCTAEiEiE. — In this family we find both unilocular and plurilocu- 

 lar sporangia, which are formed in spots on the frond, and arise from 

 the superficial cells. The former are spherical and the latter ellipsoid 

 in outline, and divided into a number of small cells. 



Des:uarestieje. — In the two preceding families the fronds were 

 either flat membranes or hollow tubes. In the present there is a solid 

 axis and numerous branches. The cells of the cortical layer are changed 

 into unilocular sporangia. The plurilocular sporangia are unknown. 



Dictyosiphoneje. — In this family the fronds are solid and branch- 

 ing as in the last, and only the unilocular sporangia are known. They 

 are in the form of large spherical cells, imbedded in the cortical layer and 

 opening at the surface. Except that in Desmarcstia the sporangia are 

 formed directly from the superficial cells, while in Dictyosiphon they 

 originate below the surface, this tribe scarcely differs from the last. 



Ectocarpe^e. — This family comprises a large number of filamentous 

 algae, upon whose branches are borne the sporangia. The plurilocular 

 sporangia are usually in the form of pod-like branches, composed of a 

 large number of small muriform cells, in each one of which is produced 

 a zoospore. The unilocular sporangia are either globose bodies, borne 

 on a short stalk, or else are formed by the direct enlargement of several 

 contiguous cells of the branches. 



Sphacelakie^e. — This family is kept distinct from the last by Thuret. 

 Both unilocular and plurilocular sporangia are known, and are similar 

 to those of the Ectocarpece. If the two families are to be kept distinct, 

 the reason must be that the fronds of the present order are solid, and 

 the growth is by the means of a single terminal cell, which is not the 

 case in the Ectocarpece. 



Leathesie^e. — In the Leathesiece and Chordariece the sporangia are 

 distributed indefinitely over the frond, but in the succeeding families 

 they are found in separate spots or bands. The Leathesiece, in which we 

 do not include Myrionema, are either in the form of small tufts, as in 

 Elachistea, in gelatinous expansions of indefinite shape, as in Petrospon- 

 giam, or in vesicular masses, as in Leathesia. The greater part of the 

 frond consists of a cellular filamentous mass, upon the surface of which 

 is borne a layer of short filaments composed of smaller cells. The uni- 



