had the opportunity of inspecting three sets [of Cuming's plants] in the Paris Herbaria, but did 

 not always find the same numbers attached to the same plant in these collections". This fact 

 would account for the want of uniformity in the numbers under which this species is quoted. 

 In the herbaria of the British Museum and of Kew it is under Cuming's number 2234, 

 whereas according to Montagne it is under 2233 in Coll. Delessert. But on the same page 

 (1. c. p. 659) Montagne cites Halimeda macroloba as n" 2233 in Coll. Berkeley; and this cor- 

 responds precisely with the number attached to H. macroloba in the herbaria of both the 

 British Museum and Kew. 



In 1878 A. erecta was described for the third time under a new name, Chloroplegma 

 papuanum (1. c.) by Zanardini, from specimens collected by Beccari at Sorong, New Guinea 

 (figs. 86, 87). Zanardini was aware of the publication of Udotea sordida Mont., because twenty 

 years earlier he had speculated as to its identity with his own Chloroplegma 'sordidum of the 

 Red Sea, which we show under A. amadelpha to be a synonym of that species. Zanardini's 

 description of Chloroplegma papuanum is one of a series of preliminary diagnoses which the 

 author intended, as he tells us (1. c. p. 34, footnote), to amplify with details and illustrations 

 in a later paper. This intention was however frustrated by his death in the same year. 



The list of synonomy shows three more names under which A. erecta has been described 

 and published. It was not till 1S89 that Messrs. Murray and Boodle placed it in the genus 

 Avrainvillea under Zanardini's specific name papuana, which title was adopted by De Toni 

 in his Syll. Alg. (1. c. p. 514). The plants figured by Messrs. Murray and Boodle (l.c. tab. 289), 

 were probably furnished by Ferguson under n° 290 of his Ceylon Algae. They certainly do 

 not represent Zanardini's type of Chloroplegma papuanum (if we may judge from the co-type). 



Such is the history of the species under its various names. According to the Interna- 

 tional Rules of Botanical Xomenclature of the Vienna Congress (1905), it is necessary to drop 

 the specific name papuana in favour of the earliest published name, which is found in Dicho- 

 nema er cc turn. There is however a remote possibility that the specific name erecta^ dating from 

 1842, may have to give way to obscura, should Anadynomene obscura Ag. (1823) prove to 

 be identical with the present species. This question is discussed on p. 33. 



A. erecta is by no means a rare alga in the Eastern Inclian Ocean, ranging from the 

 Madras coast to Xew Guinea; and its characteristic simple form and yellow filaments allow it 

 to be recognised without much difficulty. The absence of torulosity is a constant character in 

 the frond filaments and their colour is always of a more or less intense yellow, often deep- 

 ening- to an orange-brown in vouno-er filaments. The size of the filaments is however liable to 

 variation in the same plant, and even in one and the same filament, being smaller inside the 

 frond and a good deal wider where they project outside the felt-work of the frond, especially 

 round the margin of the flabellum. (For variation in size see figs. 85, 87, 88.) 



It is interesting to note that two specimens in the British Museum, one certainly and 

 the other probably collected in the Gulf of Manaar [Pearl Bank, Ceylon (Herdman) and Coast 

 of Madras (Thurston)] have the frond-filaments more slender than is usual in most specimens, 

 ranging from about 27 u to 42 a. 



Until the year 1907, the fructification of Avrainvillea had never been observed, but 



