British Marine Algae. 317 
England, told me he had found a new parasitic Floridean 
on Callophyllis laciniata : I then called his attention to the 
passage above quoted, and he told me that he felt sure the 
‘papillae’ referred to by Johnston were really the fronds 
of his new parasite, which he proposed to call Callocolax. 
I showed my specimens to Mr. Holmes, and he has since 
found the plant in the south of England and has distributed 
specimens, though hardly very characteristic ones, in his 
excellent Algae Britannicae rariores exsiccatae. I may also 
mention that specimens of Buffhamia speciosa and Tellamia 
intricata have also been distributed in the same publi- 
cation. 
The fronds of this tiny parasite occur either in solitary 
specimens or in groups composed of from three or four to 
a dozen or more individuals, and are situated on any part 
of the host-plant. The fronds are from 2-4 mm. in 
diameter and are rather irregular in shape, being either quite 
simple, or lobed, or palmate. The connexion between host 
and parasite is very intimate, the cells of the one blending 
almost imperceptibly with those of the other. Like Ricardia , 
Janczewskia , Gonimophyllum , and so many other parasitic 
Florideae, Callocolax belongs to the same family as the host 
on which it grows 5 and no doubt this fact has caused it to be 
often overlooked, as the structure of the cystocarp is exactly 
like that of Callophyllis , and the dividing line between host 
and parasite very difficult to see. When, however, as often 
happens, the host bears cystocarps and the parasite tetraspores 
or vice versa, it is not so easy for the parasite to escape 
observation. In some cases the fronds of the Callocolax are 
darker coloured than those of the Callophyllis , and I have 
found this is usually the case when the former bears cysto- 
carps and the latter tetraspores ; in the converse case the 
fronds of the Callocolax are the lighter coloured. I have 
received from Mr. T. H. Buffham tetrasporic specimens of 
this species plentifully scattered amongst the cystocarps, 
which they hardly exceed in size, of the host-plant ; they are 
situated either on the edge or surface of the frond, and are 
