460 BULLETIN OF THE BUREAU OF FISHERIES. 



acute, segments patent, attenuated at the apices; margins entire or often lacerate, smooth, often undu- 

 late; no nerves running from midrib; tetrasporangia in small or large, inconspicuous, more or less con- 

 fluent sori along both sides of the midrib; antheridial sori uniformly scattered over the frond. 



Brazil; Europe; Tasmania; Red Sea; Arabian Gulf. 



Beaufort, N. C.: Occasional on rocks of Fort Macon jetties, summer and autumn; occasional on 

 Bogue Beach, spring, summer, and autumn; extremely abundant alongshore for distance of more than 

 22 km. from New River Inlet, south of Beaufort, and extending at least 12 km. offshore, at depth of 

 5.8 to 12 m., August, 1914; very abundant in trawl offshore from Browns Inlet, south of Beaufort, 

 July, 1915. 



This species has not previously been reported from North America. The specimens from this 

 region closely resemble specimens from England and France. Those from New River Inlet are the 

 largest which have been observed by the author. 



2. Dictyopteris serrate (Areschoug) comb. nov. PI. XCIII, fig. 3. 



Haliseris serrata, Areschoug, 1847, p. 4, pi. 7. 

 Haliseris serrata. De Toni, 1895, p. 259. 



Frond 8 to 30 cm. long, 1.4 to 3 cm. wide, on an elongated, slightly flattened stipe; color yellow 

 brown; sparingly dichotomous; hairs occurring in scattered groups over the lamina; sinuses subrotund, 

 segments patent, attenuated at the apices; margins usually entire, with acute, approximate, or more 

 distant serrations; lamina furnished with more or less numerous, fairly conspicuous nerves running 

 from the midrib obliquely towvd the margins; sporangial sori small and inconspicuous, in more or less 

 regular lines parallel to the veins in the intervenous spaces; oogonia produced on both surfaces, scattered 

 over the frond, especially along midrib and margins. 



Port Natal, Africa; Mauritius. 



Fairly abundant July and August, 1903, Bogue Beach, Beaufort, N. C., occasional in spring, 

 summer, and fall of other years; several large plants dredged from the coral reef offshore, August, 1914, 

 and August, 1915. 



This species has been previously reported only from Port Natal, Africa, but a specimen in the 

 herbarium of the New York Botanical Garden was collected in Mauritius. The Beaufort specimens 

 differ from the description in having slightly more rounded apices and slightly less rotund sinuses. 

 They sometimes differ from the plate in Kuetzing (Tab. Phyc. IX, pi. 60) and from the specimen in 

 the herbarium of the New York Botanical Garden in having less conspicuous veins and smaller, more 

 numerous serrations. From the latter specimen they sometimes differ also in having a lighter color 

 and a thinner texture, the inner stratum consisting of one to two layers of cells instead of uniformly two 

 layers, as in that specimen. In spite of these differences there seems no doubt that the specimens from 

 Beaufort are correctly referred to D. serrata. They certainly belong to Dictyopteris and, if not this 

 species, must be described as a new one. The differences do not seem sufficient to warrant the descrip- 

 tion of a new species. 



In the Beaufort plants the apices are sometimes sunken, as in fern prothalli. In one specimen 

 the veins occasionally, instead of running out to the margins, form plexuses of small veins between 

 the midrib and the margin and between the dichotomies of the midrib. Both tetrasporangia and oogonia 

 have been observed on the Beaufort specimens. 



Genus 5. Dictyota Lamouroux. 



Dktyota, Lamouroux, 18090, p. 331. 

 Dictyota, Lamouroux, 1809, p. 38. 



Frond erect, flat, ribbonlike, sometimes rising from a rhizomelike, rounded portion, 

 usually regularly dichotomous, growing by a single initial cell at the apex of each branch, 

 surface uniform, zonations lacking; no midrib present; cortex composed of a single layer 

 of small cells; inner stratum composed of a single layer of rather large cells; spores pro- 

 duced four in a sporangium; sporangia occurring singly or in small groups scattered 

 over both surfaces of the frond; oogonia and antheridia produced on different plants, 



