THE ALGAE OF BERMUDA. 127 



sessile or lateral on very short pedicels, about 250 fi diam.; tetra- 

 sporangia about SO /x diam., 2-5 in a straight series, in somewhat 

 swollen, often ciu'ved ramuli. Rhizoids filiform, varying in size but 

 usually slender, attached to the substratum by a terminal disk. Type 

 in Collins herbarium. Gravelly Bay, Feb., Hervey, Fairyland, Cave 

 at Agar's Island, Aug., and dredged in 6 m., Collins. A rather dehcate 

 plant, usually on Sargassum or Zonaria, but also on limpet shells. 

 The variation in number of pericentral cells is something exceptional 

 in a plant of normally four. The increased number does not seem to 

 be limited to any part of the plant, but may occur in horizontal or 

 erect filaments, younger or older. It has some resemblance to L. 

 subadunca (Kiitz.) Falk., but that has uniformly six pericentral cells. 



2. L. Saccorhiza sp. nov.; P. B.-A., No. 2042. Cellulis peri- 

 centralibus 4; filamentis prostratis 50-70 ij, diam., segmentis 1-2 

 diam. longis; filamentis erectis numerosis, ad 2 mm. longis, 25-45 ju 

 diam., ad basin abrupte, apicem versus longissime attenuatis, prope 

 apicem folia bene evoluta sed fugacissima gerentibus; segmentis 2-3 

 diam. longis, ad apicem diametro brevioribus; filamento prostrato 

 ad plantem hospitem rhizoideis numerosis affixo a parte inferiore fila- 

 menti ortis, primo cylindraceis vel ortu complanatis axis filamenti 

 sensu, mox in saccos ovoideos expansis, ad 800 /j, longis, 160 /jl diam., 

 inter utriculos plantae hospitis penetrantes. Tetrasporangiis uniseri- 

 atis in parte superiore filamenti erecti sitis, diametrum filamenti 

 ad duplo superantibus; cystocarpiis subsphaericis, circa 100 /i diam., 

 apicibus ramorum proximis, segmentis proxime inferioribus saepe 

 ramulos breves solitarios vel paucos gerentibus. Antheridiis folio- 

 rum evolutione ortis, conico-ovoideis. Colore roseo; substantia 

 molh. Plate II, figs. 13-14, Plate III, figs.15-17. 



Pericentral cells 4; prostrate filaments 50-70 ju diam., segments 

 1-2 diam. long, erect filaments numerous, up to 2 mm. long, 25-45 ix 

 diam., contracted abruptly at base, gradually towards apex, segments 

 2-3 diam. long, at growing tip shorter than the diam.; well developed 

 but very fugacious leaves formed on the upper part; prostrate fila- 

 ments attached to the host by numerous rhizoids issuing from the 

 lower pericentral cells of the prostrate filament, one or more from a 

 segment, at first cyclindrical in section, or flattened in a line with the 

 axis of the filament, below expanding into an ovoid sac, up to 800 /x 

 long, 160 yu wide, penetrating between the utricles of the host. Tetra- 

 sporangia in a single series in the upper part of a filament, up to twice 

 the diameter of the filament. Cystocarps subspherical, about 100 fx 

 diam., near end of erect filament, one or more short branches issuing 



