504 HOWE: PHYCOLOGICAL STUDIES 
thallus surface, mostly, however, bounded by narrow reticulately 
isposed series of sterile cells. [PLATE 30; PLATE 33, FIGURES I-5.] 
La Paz, Vives 20e (type) and 2b. 
No. 20e, the larger of the two specimens seen, is antheridial and 
11d, the smaller, is sterile. The plants are somewhat Rhody- 
menioid in habit, but their structure is rather more suggestive 
of that of plants of J. Agardh’s subgenus Podeum of Gracilaria, 
though the medullary cells are more nearly empty than is cus- 
tomary in this group. However, the antheridia appear to har- 
monize much better with those of Gracilaria, so far as described, 
than with the wholly superficial or exserted and uninterruptedly 
expansive antheridia of Rhodymenia. So far as we are aware, the 
antheridia have been described in only three species of Gracilaria, 
viz., G. confervoides,* G. armaia,} and G. compressa. t 
The antheridia of Gracilaria confervoides are described and 
figured as occupying nearly closed pear-shaped cavities, the bases 
of which penetrate the subcortical layer. Those of G. Vivesii are 
more like shallow saucers, often irregular in outline, and they are 
confined to the rather thin cortex and are covered only by the 
Botanical Garden, distributed as “Gracilaria multipartita J. Ag. 
fronde latiori”’ (Vickers, Alg. Barb. 136). 
he two nearest relatives of Gracilaria Vivesti are probably 
G. Cunninghamii Farl.§ (J. Ag. Sp. Alg. 34: 93. 1901), based 
upon material from Santa Barbara, California, and Gracilaria (?) 
peruana Picc. & Grun., from Paita, Peru. Gracilaria Vivesii 
differs from G. Cunninghamii in its brighter red (less brownish) 
color, in being regularly dichotomous instead of often somewhat 
tri- or polychotomous, in its less elongate, less cuneate, and broader 
: * Thuret, in Le Jolis, Liste Alg. Mar. Cherbourg 134. 1863; Thuret & Bornet, 
Etudes Phyc. 80-82. Dl. '40. f. 1,3. 1878; Buffham, Jour. Quekett Micros. Club 
II, 5: 294. pl. 13. f. 11, 12. 18 xs 
t Thuret, Ann. Sci. Nat. IV. 3: 22. 1855; Thuret & Bornet, loc. cit. 
t Thuret & Bornet, loc. cit. 
§ This specific name appears to have originated through the misreading of a 
Ce specific name accompanying a specimen sent to Agardh by Mrs. 
