300 
Transactions of the Society. 
Genus Inactis Ktz. 
I. sp. This occurred at an elevation of about 2000 feet near 
Twll Du, on dripping rocks, forming large darJc red patches ; 
the filaments were from 1*2 to 2*5 /x in thickness. It is 
probably a variety of I. Gresswellii Thur. It is certainly 
different from I. tinctoria Thur., which I have recently seen 
on Myrio^lujUum from the Lake District. 
Genus Spirulina Link. 
S. oscillarioides Turp. C. 
Sub-class Chroococcace^. 
Order Chroococcace^. 
Genus Chroococcus Nag. 
C. cohderens Nag. A., F., C., Bettws-y-coed. 
C. turgidus Nag. S., C., F., Llyn Idwal. 
Genus Gloeocapsa Ktz. 
G. pohjdermatica Ktz. C. 
G. quaternata Ktz. Near Llyn Coron. 
G. magma Ktz. Dripping rocks, Twll Du. 
Genus Merismopedia Meyen. 
M. violacea Ktz. C. 
M. glauca Nag. P., C., S. 
Genus Aphanocapsa Nag. 
A. rimlaris (Carm.) Kabh. Penmaenmawr. 
Genus Microcystis Ktz. 
M. protogenita (Bias.) Kabh. C. 
M. marginata Kirch. C. 
Genus Codospliderium Nag. 
G. Kutzingianum Nag. C. 
Genus Gomphosphseria Ktz. 
G. aponina Ktz. C. 
Class Diatomace.®. 
Genus Gyclotella Ktz. 
G. operculata Ktz. A. 
G. Kutzingiana Thw. A. 
