HoweE: PHYCOLOGICAL STUDIES 497 
PADINA DuRVILLAEI Bory, Dict. Class. Hist. Nat.12: 591. 1827; 
Voy. Coquille, Bot. Crypt. 147. pl. 21. f. 1. 1828 
La Paz, Vives 5, 13, and 15. 
No. 13 of the material communicated consists of one young 
specimen 5-6 cm. high and one larger, apparently mature but 
sterile specimen about 12 cm. high, with its main, flabellate or 
cuneate-flabellate lobes 10-12 cm. broad. The thallus is somewhat 
coriaceous and multistratose except at the extreme margin; it is 
for the most part 8-12 cells thick, though towards the base it 
may become as much as 18 cells thick. Specimens of P. Durvillaet 
in the Muséum d’Histoire Naturelle of Paris, marked ‘“‘de la Con- 
cepcion, Chili, par Durville, 1825, . . . petits individus,’’ show a 
thickness of 8-10 cells in median portions. 
No. 5 is similar to the older plant under no. 13, but is smaller 
and more dissected. No. 15 consists of fragments distorted by 
bearing the eggs of some marine animal. 
PADINA sp. 
La Paz, Vives 3. 
A much thinner and rather more calcified plant than no. 13 (P. 
Durvillaei). The single specimen gives the impression of having 
been semiprostrate when growing, though this appearance may be 
due in part to the way the specimen has been pressed and dried. 
The plant is 6-7 cm. long or high and its rounded-flabelliform lobes 
are 6-7 cm. broad. The thallus is 3 cells thick from the base to the 
rolled margin, which is bistratose. The surface cells are oblong, 
22-68u X 22-27, while in P. Durvillaei they are quadrate and 
oblong and about 13-28 in diameter. The plant represents pos- 
sibly an undescribed species, but as several poorly understood 
species have been proposed in the genus and as our material is 
sterile, we would hardly venture at this time to suggest a new 
specific name. 
Dictyota Vivesii sp. nov. 
Densely cespitose, stupose at base, 7-9 cm. high, 135-160 
thick (240n at base), collapsed and thin on drying, somewhat 
regularly 3-6 times dichotomous below, the branches then rather 
closely 3 or 4 times subflabellately or subpinnately dichotomous, 
sinuses mostly rather acute, margins very entire or slightly un- 
