43 
newcomers has been from the south. This fact might 
indicate an amelioration of physical conditions during the 
past twenty years; but, unfortunately for the theory, 
it has been observed that about an equal number of 
species, also of more southerly distribution, seem to have 
disappeared from the flora during the same _ period. 
Comparison of the present records from the Port Erin 
Station with the lists of older collectors for Douglas Bay 
shows that about twenty species with definitely southern 
distribution are missing from the south-west corner of the 
Island. It is of course conceivable that they are inhab- 
itants of the sub-littoral zone and inaccessible to the 
collector. The most careful search has been made of the 
collecting area and the conclusion reached that either the 
Douglas Bay records were of plants detached from their 
hold in deep water and cast up by the tide, or that the 
species have actually disappeared from the flora, for they 
are not now to be found despite assiduous search even in 
their original localities. The outstanding species under 
discussion are : | . 
Cystoseiva ericoides 
C, discors 
C. fibrosa 
Phyllophora palmettoides 
Gymnogongrus Griffithsiae 
G. Norvegicus 
Nitophyllum Gmelim 
Dasya ocellata 
Seivospova Griffithsiana 
Compsothamnion thuyoides 
Ceramium fastigiatum 
C. cirvcinnatum 
Gloiosiphonia capillaris 
_ Owing to some obscure factor of the environment these 
species have not retained their place in the flora of the 
Island, but in view of the fact that the general trend of 
immigration appears to be from the south, it is possible 
that they will reappear sooner or later when ocean currents 
