SURFACE DREDGING ON THE DEE. 95 
6. Actionoplychus undulatus; Ehr. Rare. A widely distributed 
species, and abundant in many fossil deposits. 
7. Coscinodiscus radiatus, Ehr. Rare. This is also a widely 
distributed species, and the finest specimens are obtained 
from the open sea in all parts of the world. 
8. Rhizosolenia styliformis, Brightw., is a beautifully marked 
diatom. Very abundant. 
9. Chaetoceros Wighami, Brightw. Rare. This form, although 
_ growing in filaments, is so easily broken that I have never 
seen more than two or three valves together. 
- 10. Melosira sulcata (Ehr.), Kitz. Rare. This form makes up 
the bulk of many of the American fossil deposits. 
11. Lucampia striata, n. sp. Described and figured by me in 
a Paper read before the Royal Microscopical Society 
(Oct. 8th, 1879.) 
On July 12th I had another day’s dredging off Hilbre Island, 
which was also rich in all the smaller forms. I examined this 
dredging in the fresh state, and found in it the’ only living 
Foraminifera that I have met with on the surface of the Dee, 
Textularia variabilis. The absence of living Foraminifera from 
the surface of the Dee is a very significant fact, showing at least 
that the estuarine forms frequent the lower water, for the most 
part living among the weeds which cover the bottom. The 
next living form which particularly engaged my attention was 
the genus of Infusoria called Persdintum: I was led to look for 
this form, and able to recognise it, from the fact that it had 
much puzzled me when I first saw the skeleton on a piece 
of talc sent me by Count CAsTRACANE from the Adriatic, 
where these organisms attain a very large size, and the long 
sweeping horns present a marked appearance. The species was 
Macroceros. On looking over a surface dredging I have from 
Yeddo Harbour, I find I have P. (Ceratium) Michaelis, which 
has the horns very short. It is said that in warm latitudes these 
Infusoria are brilliantly phosphorescent. The lorica is described 
as membranous. It appears to me to be chitinous, and will 
withstand a moderate amount of fire and acid. In observing 
the forms obtained from the Dee, I could easily make out the 
band of cilia round the body, which was placed in an oblique 
direction, so that the animal had a rolling sort of motion such 
as you see in detached Stentors. The horns seem to have no 
motion, and I had difficulty in making out the flagellum. I am 
strongly inclined to believe that many of the species described 
by PriTcHARD are only different stages of growth. PeErRry, 
who is one of the authorities on this genus, has accepted the 
division of EHRENBERG, viz.—those. with horns, and those 
without, and in this I agree. It is said that Peridinza exist 
in the chalk beds of the secondary strata; if so, they are 
amongst the few ciliated Infusoria that have left a geological 
record. 
