52O BULLETIN OF THE BUREAU OF FISHERIES. 



Occasional on Bogue Beach, Beaufort, N. C., summer and autumn, sometimes fruiting. 



Two distinct forms, a thin, membranaceous one and a thicker, more gelatinous one, have previously 



been included under this species. Although both these forms seem to be represented under the name 



" Halymenia floridana " in Herb. Agardh a the concensus of opinion seems to be that the thin form 



"should be considered as the type, and the thick one has accordingly been separated by Collins and 



Howe (1916) under the name Halymenia gelinaria. 



The present species (figs. 45 and 46) has a rather thin, membranaceous texture; the structure is 

 fairly dense, the cortex consisting of one or usually two layers of medium-sized cells apparently formed 

 from the ends of filaments, bounded by a definite cuticle ; the medullary portion is densely filled with 

 jelly and is traversed by rather scattered, irregularly branched filaments, segmented occasionally, but 

 not conspicuously, the majority of these being small but mixed with occasional larger filaments, both 

 kinds being irregular in size, anastomoses appear infrequent and inconspicuous in section; in surface 

 view the surface appears composed of small, roundish-angular cells situated close together; a subepi- 

 dennal view seen from the surface shows conspicuous anastomoses of filaments and numerous hetero- 

 morphous "stellate ganglia" apparently formed from the enlarged ends of the larger filaments, from 

 which radiate filaments running parallel with the surface and frequently fusing with similar filaments 

 from other similar ganglia; the color is rather dark, rose or purplish pink. 



This species is distinguished from Halymenia gelinaria by its thinner, more membranaceous texture, 

 its denser structure, its small cells seen in surface view, its heteromorphous "stellate ganglia" seen in 

 subepidermal view, and its more rosy color. Its cystocarps also appear to the naked eye smaller and 

 denser than in H. gelinaria. 



From Chrysymenia agardhii, which it somewhat resembles, it is distinguished by its more mem- 

 branaceous texture and its thinner, denser frond, with smaller cells and more numerous internal fila- 

 ments. It is distinguished from Callymenia reniformis (Turn.) J. Ag., with which it has often been 

 confused, by its thinner, more membranaceous, less gelatinous frond, with denser, more regular 

 structure. 



This is the northern known limit of the species and of the genus. 



Genus 2. Grateloupia Agardh. 



Grateloupia, Agardh, 1822, p. 221. 



Frond flattened, dichotomously or laterally branched in the plane of the flattening, 

 primary frond sometimes simple or irregularly divided, often irregularly proliferous 

 from the margins and sometimes from the flat surfaces; structure filamentous, inner 

 (medullary) layer composed of thin, segmented, reticulately anastomosing filaments, 

 sometimes rather lax, inner cortex moderately thick, lax within, gradually passing over 

 into the medullary portion, outer cortex rather thick, composed of vertical, moniliform 

 filaments; tetrasporangia scattered over the frond, embedded in the outer cortex, 

 cruciately divided; antheridia arising from the outer cortical cells, forming patches over 

 the surface of the frond ; cystocarps scattered over the frond or forming irregular groups, 

 small, inconspicuous, entirely sunken within cavities in the cortical layer, communicating 

 with the exterior by an opening formed among the cortical filaments, bearing numerous 

 carpospores in irregular groups radiating from a central point. 



About 35 species, mostly in warm seas. 



KEY TO SPECIES. 



Fronds decompound-pinnate, narrow linear, 0.5 to 2.5 mm. wide i. G. filicina (p. 521). 



Fronds rather simple or irregularly divided, finally pinnate from the margins, main axis 0.5 

 to 4 cm. wide 2. G. gibbesii (p. 521). 



a The author is indebted to Dr. Marshall A. Howe for information regarding specimens placed under this species in Herb. 

 Agardh. 



