ON THE GENERA ANADYOMENE AND MICRODICTYON. 69 
plurimis inter seseque anastomosant, nec ut solenne est in congeneribus 
membrana ulla conjuncta sunt.—JMontagne in l. c. A. Calodictyon, 
Montagne in Webb and Berthelot, Fl. Canar. iv. 180. t. 8. f. 1 (1850). 
M. Agardhianum, Decaisne, Arch. du Mus. ii. 115, 117, not Endl. AM. 
Montagneanum, Endlicher, Mantissa, ii. 14. M. Calodictyon, Decaisne ; ` 
Kützing, Sp. Alg. 512. 
AB. Atlantic Ocean, Canaries, Webb and Berthelot. 
2. M. Montagnei ; filaments moderately thick, the colour white or 
yellowish when dry.—* Microdictyon Montagnei," Harvey, Algæ Insul, 
Amicorum Exsice. n. 89. 
Has. Friendly Islands, Harvey, Herb. Brit. Mus. 
The specimen of M. Montagnei, no. 89, from Professor Harvey's 
collection, of specimens of Australian d/ge in the British’ Museum, 
is very distinct in the large size of the cells, in the distribution of the 
branches, and in the colour of the dried specimens, from the other Aus- 
tralian and the Natal specimens in the Museum. 
3. M. Kraussii ; filaments very slender, filiform; frond flat, divided 
into wedge-shaped lobes from a central disk, having several more or 
less imbricate lobes at the centre; colour blackish when dry; Calodic- 
tyon.—M. Velleyanum, ** Decaisne;" Krauss, Pflanzen des Cap- und 
Natal-landes in Flora, 1846, 215, ** in Batav. 210." 
Has. S. Africa : Natal, Krauss, n. 273, Herb. Brit. Mus. 
** Frond flat, foliaceous, imbricate at the base. 
4. M. tenuius.—Hydrodictyon umbilicatum, var. tenuius, Agardh, 
Syst. Alg. 85. M. fenuius, Decaisne, Ann. Se. Nat. 2 ser. xvii. 327. 
M. Agardhianum, Endlicher, Mantissa, 14, not Decaisne. 
Has. Red Sea, Djedda, Botta, Herb. 
* The specimens from the Red Sea are aid than that described by 
Velley, forming a kind of simple, foliaceous, flat expansion, at the centre 
of which grows a considerable number of lamellæ.”—Decaisne, Arch. 
du Mus. ii. 116. 
Genus 2. PHYLLODICTYON, n. g. 
The frond oblong, free, lobed or confluent ?, arising from a slender- 
branched articulated filament; the basal filament elongate, with 
opposite branches, each ending in a frond with a central rib, giving 
off close opposite branches at right angles to the main stem and each 
other. 
