1 



MRS. A. WEBEIi-YAN BOSSE ON THE 



The central cell is surrounded normally by four pericentral cells, but between these 

 other large cells soon/ appear and' numerous hyphcc develop in the membranes. I have 

 not seen them enter the pericentral cells as they do in T. Bornetii, but it may be that 

 this takes place in the basal part of the frond. A layer of small cortical cells surrounds 



mam 



The latter has a winged appearance on account of the pericentral 



of the spine-like lateral branches growing sideways together with it for a few segments. 

 Adventitious branches appear occasionally on the dorsal side of the frond in the axil 

 of lateral branches, but they remain short ; in T. Bornetii these branches attain full 



development. 



The characteristic dorsi-ventral organization of T. Bornetii is far less conspicuous in 



T. Mhelce, and shows itself in barren specimens only in the rudimentary axillary 



branches. No organs of fructification were present, and it was only because I was 

 familiar with the genus that I was able to name the specimens from Amirante. 



Heterosiphonia, Montague. 



1. IlETEROSiPnoNiA Eendlei, u. sp. (Plate 12. figs. 11, 12.) 



Thallo fasciculato, pluribus ramis principalibus e callo basali surgentibus; ramis 

 principalibus totis ecorticatis, pauce ramosis, penicillos ad segmentum quod que 

 secundum, distichos et altemantes gerentibus. Cellulis periceutralibus 7-8-10. 



Penicillis ramulos unilaterales et stichidia potius obtusa quam acuta ferentibus 

 tetrasporis instructis. Antheridiis et cystocarpiis ignotis. Thallo alto 8 cm. 

 Cargados Carajos, 47 fms. ; dry specimen. 



I believe Ueterosiphonia Bendlei * to be a new species because none exists amongst 

 the JIeterosip7i07ii(B ecorticatce that is exactly like it. It belongs to the small group with 

 more than four pericentral cells, the branches or penicilli of which arise at a distance 

 of two or three segments from each other and are turned regularly to the right and 

 left. H. JRendlei stands nearest to H. suhsectmdata (Suhr), Palk., but differs in the 



ri 



pericentral cells not being transversely divided. 



The principal axis has a height of about 8 cm. ; it is erect and carries small horizontally 

 spread penicilli which have unilateral monosiphonous branchlets incurved at the top. 

 The number of pericentral cells in the main axis varies from 6-10, and the segments 

 are three times as broad as long. In the penicilli the few basal polysiphonous segments 

 are almost as long as broad or a little broader. 



I have soon neither cystocarps nor antheridia, only stichidia, which are borne on the 

 side-branches of the penicilli ; they are elongated, with a blunt apex. 



2. Heterosiphonia spec. 



Coetivy, reef ; dry specimen. 



This is a small specimen, 1 cm. high ; it grows on Codium. 1 failed to recognize it 

 amongst the described species and yet do not dare to describe it as new. 



♦ Xamed in honour of Dr. Cendle, Keeper of the Botanical Department of the British Museum, renowned fjr 

 the kind hospitality that it offers to every visitor. 



