50 



is carried through more regularly the shoots get a Struvea-like 

 appearance (Fig. 34 b and c), sometimes also and especially in 

 the uppermost part of the branches each cell only bears a single 

 branch and these are arranged secundly upon the 

 lowermost side of the upward curved mother bran- 

 ches (Fig. 34, a). But as a rule the ramification is 

 very irregular and new adventitious branches con- 

 tribute to it. 



The cell-division (Fig. 35) is, so far I have been 

 able to see, carried out by segregative cell-division 

 and quite in the same way as I have found it in 

 Cladophoropsis. The uppermost end of the filaments 

 grows rather long and the protoplasm together with 

 the chromatophores, nuclei etc. is then at once 

 divided in 2 — 4 parts in proportion to the length 

 of the filaments; these parts grow again closely 

 together, being now separated by a wall. 



The thick primitive filaments reach a dia- 

 meter of about 160^ — 200/-^ seldom even 300 ,«, the 

 ramuli about 70 — 100^. 



At their base the quite young branches lack 

 (About 25:1). cross walls but in older parts of the thallus it is 

 only exceptionally that these are not found. 



The entangled filaments are further fixed together by means 

 of the rather numerous tenacula, found at the apices of the bran- 

 ches (Fig. 34 d, e). They have a cross wall at 

 their base and a richly ramified attachment disc, 

 by means of which they are strongly fixed to 

 the neighbouring filaments. 



The small chromatophores are parietal and 

 connected by thin threads to a network (Fig. 36) ; 

 in each chromatophore a pyrenoid is present. 

 The numerous nuclei are arranged regularly in SiameHsisjie'mh. 

 the wall plasma. P^^^|^ °^shmvilf- 



I have not succeeded in finding fertile cells in chromatophores 

 my collections but in the Siamese specimens such ^"^t^yp!*^^' 

 occurred ; the whole cell is transformed into a 

 sporangium and the zoospores escape through a rather large hole 

 on the one side of the sporangium (Fig. 34 /). 



This species was found in shallow water in rather sheltered 

 places where it was growing in crevices in rocks. 



Fig. 35. Boodlea 

 Siamensis 



Reinb. 



Summit of 



filament in 



cell division. 



mm 



Fig. 36. Boodlea 



