ao d . Zanardini (in Mem. Ist Veneto VIL \>. 190 tab. 



VIII, : conspecific with Avrainvillea amadelpha. 



is the type, and for twenty years the only species, ol 

 1, which is tlnis merely a synonym ol Avrainvillea. 

 In the same j •■ published rab. Phyc. VIII. p. 13, tab. 28 his genus 



i which he placed t\\<» species R. tomentosa and R. longicaulis, both found in the 



ieci< - is concerned, the genus Rhipilia holds good; but 

 Ivrainvillea, and though it lias been referred tirst to one and 

 ither West Indian s] we are strongly of opinion that it is identical with a 



1 (p. 41). In 1874, Dicku (in Journ. Linn. Soc. (Bot. XIV. p. 151) 

 ither species, R. Rawsoni from Barbados, subsequently placed by Mi rray 

 in Avrainvillea as a synonym ol one of the species, but recently shown to 

 bj Dr. Howe, namely . /. Rawsoni. 

 papuanum Zanardini (1878), Chlorodesmis pachypus Kjellman ('1879 — 8' 

 Rhipilia Andersonii Murray (1886), and Avrainvillea papuana Murray & Boodle are all syno- 

 nymous with -•/. erecta y mentioned above. 



In 1887, f. G. Agardh (Till Alg. Syst. V. p. 84) supplied a description to Avrainvillea 

 . a species which had been issued several years previously without description by 

 Harvey in his Friendly Islands Exsiccatae as Udotea lacerata. 



The only attempt hitherto made to monograph the genus was that of Murray and 



in 1889 (in Journ. of Botany XXVII pp. 67 — 72, 97 — 101), in which they gave a 



• ry of the genus, a systematic arrangement of the species, and an account of the structure. 



nise seven species of Avrainvillea and also include in the genus Chlorodesmis 



comosa, and with some reservation, C. caespitosa — an arrangement of which we do not our- 



pprove. 



In 1905 and 1907 Dr. Howe (in Buil. Torrey Bot. Club XXXII. p. 565; XXXIV. p. 507) 



ited of the West Indian species, recognising tour species which he carefully describes 



and some which he figures. He also gives an account (op. cit. XXXIV p. 504' of the sporangia 



of Avrainvillea nigricans f. fulva which he had the good fortune to hnd on a specimen 



gathered in Montego Bay in January 10.07. The spores, few in number, are contained in the 



inflated ends of filaments which project trom the surface of the frond. Since his account was 



i we have ourselves noticed similar sporangia, but void of spores, in typical A. nigricans 



la and in a form of A. nwta collected by Thurston in the Gulf of Manaar, 



imen being preserved in alcohol in the British Museum. 



We »und it necessary during our present study of the genus to establish five new 



1 the following localiti< Port Phillip and Christmas Island in the Indian Ocean, 



here in the Pacific Ocean, Canary Islands and Grenada in the Atlantic. 



tant characters for distinguishing the species ol Avrainvillea we have 



ind nature of the filaments composing the frond. whether cylindric, torul 



im< ti or tapering towards the apices, whether tortuous or straight. 

 For the proper appreciation and comparison of these data it 



