Howe: Phycological studies 509 



from "Golden Gate, California," but they agree closely in habit, 

 color, and structure. 



The pericentral siphons are usually ten in number but vary 

 from nine to eleven. The basal internodes are 6-10 times as long 

 as wide. Simple colorless monosiphonous "leaves" are abundant 

 at the tips. 



Centroceras clavulatum (Ag.) Mont, in Durieu, Fl. Algerie 1 : 



140. 1846 

 Ceraminm clavulatum Ag. in Kunth, Syn. PI. Aeq. 1: 2. 1822. 



La Paz, in the herbarium of the New York Botanical Garden, 

 ex herb. C. L. Anderson, collector unknown. 



The fragmentary specimen is from a stouter and more spiny 

 plant than the original Ceramium clavulatum Ag., which was 

 brought from Callao, Peru, by Humboldt. It also has shorter 

 internodes and more forcipate apices. It suggests Kiitzing's figures 

 of his Centroceras oxyacanthum, drawn from a South African speci- 

 men, though originally described from Cuban material; however, 

 the spines are less conspicuous than in C. oxyacanthum and are not 

 much in evidence, except at the apices. 



The type of C. clavulatum in herb. Agardh is a slender plant 

 with rather strict dichotomies, the tuft standing about 3.5 cm. 

 high. The filaments are 85-110^1 in diameter; the internodes are 

 320-510^ long below, becoming about 8o-ioOju long under the 

 terminal dichotomy; the apices are incurved only in the youngest 

 growth stages and are scarcely forcipate in the usual sense of the 

 term; no lateral innovations were noticed; the spines are few, 

 small, erect or incurved, and very inconspicuous, consisting of one 

 or two cells and rarely reaching a length of 40/i. Kiitzing was 

 doubtless right in suspecting* that the original Ceramium clavu- 

 latum belonged with his own Centroceras cryptacanthum, of w T hich 

 his var. /3. longiarticulatum came from the coast of Peru, the type 

 region of Ceramium clavulatum Ag. 



Halymenia actinophysa sp. nov. 



Thallus plane, sessile (?), very thin (70-1 30,11), gelatinous- 

 membranous, elliptic-obovate or irregularly orbicular, attaining 

 a length of 30 cm. or more and width of 20 cm., occasionally and 



* Linnaea 15: 742, 743. 1841. 



