492 Howe: PHYCOLOGICAL STUDIES 
and #7. Tuna, using for her studies of the latter, through the 
courtesy of M. Ed. Bornet, ‘a portion of the identical specimen ” 
described by Derbés & Solier. Mrs. Gepp in this paper brought 
out some especially interesting facts in regard to the relation of 
the sporangiophores to the filaments of the central strand. 
In 1905, in distinguishing the newly recognized species Hat- 
meda scabra, an ally of H. Tuna from Florida and the Bahamas, the 
present writer * described and figured its sporangia and alluded to a 
fertile specimen of H. Tuna collected in Bermuda. In view of the 
rarity of the occurrence of fertile specimens in this genus, it may 
be remarked that the Bermuda specimen was found in the month 
of June and the Florida specimen of H. scadra on March 30. 
In each of these cases only a single plant out of the many 
observed was fertile. But on March 3, 1906, near the mouth of 
the main harbor of Culebra Island, Porto Rico, the writer found, 
growing near the low-water mark, an abundance of Halimeda 
Tuna laden with sporangia. The photograph published herewith 
(PL. 27, Fics. 2-4) gives an idea of the appearance of these fer- 
tile specimens and of the position of the sporangia upon them. 
The sporangia occur chiefly in crowded clusters on the margins of 
the segments, but they are also often scattered over the discs or 
flattened faces of the segments, which they occasionally cover 
almost completely. Derbés & Solier and Mrs. Gepp describe and 
figure the sporangia of Halimeda Tuna as occurring only on the 
margins of the segments, but Zanardini both describes and illus- 
trates them as occurring also on the discs, The sporangiophores 
are I-2 mm. long and both in these Porto Rican and in the Ber- 
mudian specimens they are apparently rather more simple (PL. 25, 
FIGS. 7-9; PL. 28, FIGs. I and 2) than those of the European /. 
Tuna ; at least, we have never observed the forking which Mrs. Gepp 
has described and figured (/. ¢., f. 6) as occurring immediately after 
the fusion of their basal filaments. All the sporangiophores that we 
have seen are either simple or once dichotomous near the top — 
somewhat resembling Derbés & Solier’s figure 2, Those spring- 
ing from the margins of the segments (PL. 25, FIGS. 8, g, 10) afe 
formed by the fusion of two or three filaments of the central strand, 
but those springing from the discs or flattened faces come directly 
morgen 
* Bull. Torrey Club 32: 241-244. Dh. 2h, ha 1905. 
