\ N | are inclined to place il near Rhipilia 



, ;„ , u , \ with Flabellaria minima. Rhipilia and Cladocephalus are 



flabelliform and excentrically infundibuliform and zonate 



(ilaments dichotomously divided without constrictions 



and bul in Rhipilia the pseudo-lateral branch terminates in a 



i ladocephalus it divides repeatedly and dichotomously 

 ibyrinthine corti 



losel) allied to Callipsygma and suggests its ancestry. 

 up, the Udoteae, we find that the most primitive forms known 

 and Penicillus Sibogae which indicate the ancestry < l" Penicillus, 

 in alternating planes. Another simple but slightly lcss primitive form is 

 which may b< traced all the other species of Udotea, as shown in the table. 

 ptionally interesting genus in view of the series of developrhental stages 

 I by its various specii 

 R 'ia lus phoenix might be thought to spring hom Udotea javensis; but the con- 



A'. oblongus with that species is less convincing. Tydemania and Halimeda are 

 I by their periodically interrupted growth and show a striking parallelism of habit, 

 combined with differences ol detail. Tydemania consists of a chain of contiguous open uncorticated 

 glomeruli strung together, so to speak, on a monosiphonous main axis (see p. 64); while in 

 the chain consists of contiguous closed corticatetl flabelliform articuli lor internodes) 

 strun ier on a polysiphonous axis. 



I or the further elucidation and revision of the truc affinities between the genera of 



ie, it is much to be desired that a study W- made of the youngest stages of growth 



in Rhipocephalus), as well as experiments in regeneration (see p. 73); also that fresh genera 



and species may be discovered to aid in linking up the genera already known. 'I he Siboga 



rial nas supplied two new genera — Tydemania and Boodleopsis — the former of which 



emarkable for its dimorphic habit and interrupted growth. 



Distribution. The Codiaceae flourish especially in tropical seas. Some of the genera 



fined to the tropics, namely, Chlor odesmis \ Rhipilia, Cladocephalus, Rhipidodesmis, 



Tydemania, Rhipocephalus. Some occur in the tropical and extra-tropical zones, 



nami Xvrainvillea, Penicillus, Udotea, Halimeda. The resl are found only outside 



tmely, Pseudocodium, Rhipiliopsis, Flabellaria, Callipsygma. 



iring now East with West, we find the five large genera, Codium, Avrainvillea, 



Halimeda, widely distributed in both hemispheres, where also Rhipilia and 



'■ more locally. Seven genera are known from the Eastern hemisphere only, 



Chlor odesmis, Rhipiliopsis, Rhipidodesmis, Callipsygma, Boodleopsis, 



bhalus is confined to the West Indian region, and Flabellaria to the 



monographed in the present paper only one, Udotea flabellum, is 



I .i i and West, being indeed widely distributed throughout the 



of Halimeda and Codium have a like distribution last and West. 



