Howe: Phycological studies 41)7 



Padina Durvillaei Bory, Diet. Class. Hist. Nat. 12: 591. 1827; 

 Voy. Coquille, Bot. Crypt. 147. pi. 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. Durvillaei 

 in the Museum 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, 

 22-68/1. 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/z 

 thick (24.OJU 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- 



