original plant, but the only specimen of Halimeda which had been collected by Duchassaing 

 at Guadeloupe bore the inscription : "Halimeda incrassata in Guad. leg. Fr. Duchassaing". 

 This plant M. Hariot was good enough to send me and both its internal structure and 

 external form are those of II. incrassata f. typica. The lower joints are very thick and much 

 calcified, while the upper joints are of the usual tridentate type common in H. incrassata. If 

 this plant should be the original of the var. tridcntaia, it becomes impossible to maintain 

 triden tata as a form. The var. triden tata Duchass. is absorbed into forma typica and the name, 

 which would have wel] described my forma tripartita, must disappear to avoid future confusion. 

 This species has only been recorded from the tropics. It is fairly common in the West 

 Indies and occurs also in the Indian and Pacific Oceans. 



Species inquirendae. 



Halimeda brevicaulis Kützing, Tab. Phyc. vol. VUL 185S. p. 11. Tab. 25. fig. II. 

 Halimeda nervata Zanardini, Plant. Mar. Rub. in Mem. Ist. Ven. vol. VIL 1859. p. 289. 



Tab. XII. fig. 2. 

 Halimeda rectangularis J. G. Agardh, Analecta Algologica, Cont. I. 1894. p. 100. 



