F. Børgesen: Rhodophyceæ of the Danish W. Indies. 



53 



Fila endophytica irregulariter ramosa sub cellulis epider- 

 malibus hospitis horizontaliter repentia, e cellulis medio plus 

 minus irregulariter inflatis constructa. 



Fila erecta, ad 500 // alta, ramosa, apicem versus sensim 

 attenuata, e cellulis ad basin 7 — 8 // latis, superne 2 — 3 fi. latis, 

 inferioribus c. 24// longis, superioribus c. 50// longis et subhya- 

 linis constructa. 



Chromatophorum parie- 

 tale pyrenoide laterali in- 

 structum. 



Sporangia oblonga, 14/« 

 longa et 8// lata in ramulis 

 unicellaribus solitaria vel 

 bina, raro sessilia adsunt. 



Fig. 55. Acrochætium repens nov. spec. 

 Two erect ramified filaments with spor- 

 angia and the basal creeping part. 

 (About 300 : 1). 



Fig. .56. Acrochætium repens nov. 



spec, a and b, erect filaments with 



sporangia, c, endophytic, basal 



filaments seen from above. 



(About 260 : 1). 



This species was found upon a Gracilaria-like plant. The 

 endophytic filaments creep below the surface cells of the host 

 (Fig. 55), forming a nearly reticular expansion (Fig. 56 c). The 

 basal filaments are irregularly ramified, consisting of barrel-shaped 

 or more irregularly formed cells more or less swollen in the middle 

 and much tapering towards both ends. 



