A STUDY OF THE GEXICULA OF COKALLIN.i:. 5 



I. Linear: the majority of Corallina, Jania and some of Amphiroa 

 belong to this type. As for the basal genicula, most of the members 

 come under this category. The exceptions are the greater number of 

 the Eurytion, Amp. Charoides, Amp. stelligera etc., and many species of 

 Cheilospomm (Fig. A). 



The gap between the articuli is very narrow, apparently seen 

 only as a circumscribing slit around the geniculum. This sort of 

 genicula has been called " lineseform " by the former systematists. 

 In these the genicula are not so short as they appear from the external 

 side. Both ends of the articuli which hold the geniculum between 

 them are concave. Hence the greater part of the geniculum is 

 covered by the overhanging margins of the relating articuli. I shall 

 call this marginal portion, for sake of convenience, the circum- 

 genicular cortex (PI. fig. 1-2). 



<=*=? ] 



The genicula of Amp. aspergillum, when judged by the external 

 appearance, come under this category. But the internal structure of 

 the frond in this species is quite different from that of the other 

 members of the Corallinœ. As it will be treated further in the 

 following pages, we can not clearly distinguish the genicular and the 

 articular portions in its internal structure. 



II. Spotty : many of the section Arthrocardia, Dene, belong to 

 this type, especially those which have the sagittate articuli ending 

 in narrow base. (fig. B). 



