Howe: Phycological studies 493 



obovoid, the longer axis being nearly always in the longitudinal or 

 vertical plane rather than in the transverse. As in Hawaiian 

 specimens, the utricles of the subcortial layer are smaller and 

 less bullate than in the plants of southern Florida and the West 

 Indies, but they have a maximum diameter of 68-175^ and are 

 always much larger than the peripheral utricles; they also form a 

 compact flat-topped stratum, very different from anything that 

 occurs in H. Tuna. The firmly coherent, often interlocked and 

 fusing peripheral utricles, and the light calcification, together with 

 the characters previously mentioned, leave no doubt as to the 

 correctness of identifying the plants with H. discoidea. 



The finding of a Halimeda on the coast of Lower California is 

 of particular interest in extending our knowledge of the distribution 

 of this genus. So far as is known to the writer, the only previous 

 record of the occurrence of a Halimeda on the Pacific coast of 

 the American continents is that given by Miss Ethel Sarel Barton 

 [Mrs. Gepp] in her monograph of "The Genus Halimeda, 1 ' where, 

 under the stations for Halimeda Tuna, is given "Payta, Peru, 

 Sinclair." 



Codium tomentosum (Huds.) Stackh. Ner. Brit. xxiv. 1797 



Fucus tomentosus Huds. Fl. Angl. 584. 1778. 



La Paz, Vives 8 and 14. 



The specimens from Baja California communicated under the 

 above numbers are a little more rigid than is usual in Codium 

 tomentosum, and the walls of the peripheral utricles are for the 

 most part conspicuously thickened at their apices, being there 

 commonly 8-27^ thick, though occasionally only 3-4^- We find 

 no trace of a mucro even in the younger parts and can discover 

 no sufficient ground for considering the plants distinct from C. 

 tomentosum, with which they agree w r ell in size and habit. The 

 thickened apices of the utricles are slightly suggestive of those of 

 the Australian Codium galeatum J. Ag., but they are not con- 

 tracted-umbonate as in that species and the plants have not the 

 size and habit of that species. Certain Jamaican specimens which 

 we have referred to C. tomentosum, sometimes have the apical 

 walls of the peripheral utricles even more thickened than in these 

 plants from Lower California, and European specimens occasion- 



