206 
Epithemia Musculus Nitzschia sigmoidea 
Campylodiscus cribrosus "5 dubia 
Surirella striatula 3 reversa 
»  lineafis And an undetermined species - 
Tryblionella marginata Navicula elliptica 
5 scutellum $5 convexa 
i punctata Westii (?) 
ee gracilis zs didyma 
a acuminata $5 pusilla 
Cymatopleura elliptica ” punctulata 
Triceratium Favus 3 palpebralis 
i striolatum Pinnularia divergens 
Bi undulatum Stauroneis pulchella 
Cyclotella Kutzingiana Cocconema parvum 
5 operculata Pleurosigma balticum 
And three species undetermined > Hippocampus 
Actinocyclus undulatus op angulatum 
a senarius ts acuminatum 
3 septenarius o distortum 
Hf octonarius Doryphora Amphiceros, vars. 
i nonarius = Boeckii 
EKupodiscus Argus, two vars. Achnanthes brevipes 
tf radiatus Grammatophora marina (?) 
A maculatus Biddulphia aurita 
Coscinodiscus radiatus Zygoceros rhombus 
, minor Dentricella sp. 
Ss eccentricus Orthoseira sp. 
3 Thwaitesii Dictyocha 
And an undetermined species Bacteriastrum furcatum (?) 
Cocconeis Pediculus x curvatum (?) 
scutellum 
29 
Some of the species in the foregoing list have been described as 
new to Britain by Mr. Roper, in a late paper, published in the 
‘Microscopical Journal. The Coscinodiscus not named seems from 
the description to be the same with that found at the mouth of the 
Thames, and is an exceedingly beautiful disc. The four species of 
Actinocyclus are those described by Ehrenberg, and are new British 
species. They exhibit the strong siliceous cellular tissue underneath 
the moniliform structure of the surface, as in Actinocyclus. The 
examples of Triceratium striolatum, and also Zygoceros rhombus, dif- 
