160 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Suborder SPONGIOCARPE.E. 



Fronds solid, cylindrical, branching; antheridia in spots on upper 

 part of fronds ; tetraspores cruciate, immersed in the cortical filaments ; 

 cystocarj)s in external wart-like protuberances, composed of parallel 

 filaments, spores obovate, densely packed around the surface of a cellu- 

 lar mass which surrounds the tip of a short pedicel. 



The present suborder was made by J. G. Agardh and Harvey to include a single 

 species, Polyides rotundus, a species in several respects anomalous. The development 

 of the cystocarps of that species was first made out by Thuret and Bornet, and a de- 

 tailed account was published in the Etudes Phycologiques. In its development the 

 cystocarp of Polyides resembles that of the genus Dudresnaya. There is produced from 

 the cells at the base of the trichogyne a number of filaments which wind amongst the 

 short filaments, of which the wart-like bodies near the tips of the fronds are formed. 

 These filaments come in contact with certain cells of the protuberances, which then 

 divide and produce the spores. Although this indirect fertilization of the carpogenic 

 cells by means of winding filaments is the same as is found in Dudresnaya, the mature cys- 

 tocarp is different in the two genera. In Polyides the ripe spores are arranged til a regu- 

 lar layer around a small placenta, which is borne on a short pedicel produced from the 

 carpogenic cell. In Dudresnaya coccinea the spores are irregularly grouped around a 

 placenta surrounding the carpogenic cell itself. In D. purpurifera, however, accord- 

 ing to D. Bornet, the cystocarps more nearly resemble those of Polyides, and he thinks 

 it not impossible to unite the two genera in one suborder. 



POLYIDES, Ag. 



(From iroXvc, many, and idea, form.) 



Fronds cylindrical, dichotomous, composed of interlaced branching 

 filaments, consisting of elongated cells and curving outwards at the sur- 

 face so as to form a cortical layer of horizontal filaments ; antheridia iii 

 patches on the upper part of frond, consisting of short, densely packed 

 filaments bearing clusters of antherozoids ; tetraspores cruciate, im- 

 mersed in the cortical layer ; cystocarps in wart-like protuberances on 

 the upper part of the frond. 



P. rotundtjs, Grev.; Phyc. Brit., PI. 95. 



Fronds blackish red, cylindrical, cartilaginous, three to six inches 

 long, attached by a disk, with an undivided stipe, which becomes above 

 repeatedly dichotomous, apices obtuse ; warts flesh-colored, numerous 

 on the upper divisions of the frond. 



On stones in deep pools and in deep water. 



Common from New York northward ; Europe. 



A species easily recognized by its regularly dichotomous, cylindrical frond, by its 

 dark, almost black, color, and dense cartilaginous substance. When sterile it might 

 be mistaken for Furcellaria fastigiata, a common species of Northern Europe, which 

 may be expected to occur on our coast. In fruit, however, they are easily distinguished, 

 since the cystocarps of Pohjides are borne in external warts, while those of Furcellaria 



