MARINE ALGJ3 OF BEAUFORT, N. C. 511 



In spite of its small size, this is the most favorable species found in this region for the study of the 

 structure of the procarp, the process of fertilization, and the development of the cystocarp. Since all 

 the organs are entirely external, these structures appear with diagrammatic clearness, and fruits of all 

 ages are often found in great abundance. 



Genus 2. Griffithsia Agardh. 

 Griffitsia, Agardh, 1817, p. XXVIII. 



Frond erect, filamentous, composed of simple rows of large, more or less long, cylin- 

 drical, barrel-shaped or obovoid cells, naked or possessed of whorls of evanescent, short, 

 branched filaments, branching lateral or dichotomous ; tetrasporangia occurring in ' 

 whorls at the nodes, or on the inner side of short, fascicled branches, usually surrounded 

 by sterile filaments, triangularly divided; antheridia forming compact tufts occupying 

 positions similar to those of the tetrasporangia or densely covering the apices of terminal 

 segments; cystocarps terminal on greatly shortened branches, sometimes appearing 

 lateral at the nodes, usually several occurring together, inclosed by a tuft of sterile fila- 

 ments, having one or, rarely, two gonimoblasts, gonimoblast usually compact, sometimes 

 divided into several lobes, forming carpospores from nearly every cell. 



About 25 species, especially in warm seas. 



One small fragment found on Bogue Beach, Beaufort, N. C.; August, 1904, seems, 

 from its structure, to belong to this genus, but is insufficient for specific determination; 

 several fragments showing the characteristic structure of the genus (fig. 43) were dredged 

 from the coral reef offshore, August, 1914. 



Genus 3. Callithamnion Lyngbye. 



Callithamnion, Lyngbye, 1819, p. 123. 



Frond erect, filamentous, composed of simple rows of cells, naked' or, in many species, 

 the main filaments corticated below by rhizoidal, descending filaments, branching 

 abundant, dichotomous or lateral, in the latter case radial throughout, or distichous 

 above, structure monopodial or sympodial, cells multinucleate ; tetrasporangia occur- 

 ring singly or in groups on the upper side of segments of upper branchlets, triangu- 

 larly divided, sometimes transversely bipartite; antheridia forming small compact 

 tufts of branched filaments of various forms situated on the upper side of upper branchlets; 

 procarps occurring singly or in rows, intercalary on the upper branchlets, usually having 

 two opposite auxiliary cells; cystocarps borne laterally on upper branchlets, some- 

 times appearing terminal, usually containing two gonimoblasts, sometimes only one, 

 gonimoblasts divided into several successively formed, rounded lobes, producing numer- 

 ous carpospores, pericarp and encircling branches lacking, but cystocarp inclosed 

 by thin, gelatinous covering. 



About 40 species, all marine, very difficult of determination, widely distributed, 

 especially in warm seas. 



This genus, which is abundantly represented in some other regions, has few species 

 or individuals at Beaufort and has not been observed by the author elsewhere within 

 our limits. The single species identified at Beaufort (C. polyspermum) is, however, 

 reported from Charleston, and representatives will probably be found in other localities 

 along our coast. In determining species, the habit and manner of branching are 

 important characters, and as these distinctions are often difficult to make and some 

 species are variable in these respects, determinations can be made only by careful 

 comparison with authentic specimens. 

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