STILL FOUND IN A LIVING STATE. 335 
tober 17, whilst writing, and whilst delivering my lecture, had 
before me, with their inner organs still well-preserved, Actino- 
cyclus senarius, Gallionella sulcata, and Coscinodiscus Patina, 
the principal forms of the chalk marls of Sicily. Nor was it these 
species alone, so remarkable from their diffusion in the chalk for- 
mation, that were found in the water which | had procured for 
examination, but with them were also living a great number of 
invisible animalcules, exceedingly interesting, at least in a sy- 
stematic point of view. Five of them are so peculiar in their 
structure, that they will form in the system of the polygastric 
animals four new genera, which I designate as 
EHucampia, 
Lithodesmium, 
Triceratium, and 
Zygoceros. 
One or perhaps two other hitherto unknown forms from Kiel 
could only be placed with difficulty under genera already known: 
and for arrangement in the system must be separated as 
Dinophysis, and 
Ceratoneis. 
The following list contains those marine animalcules from 
Cuxhaven observed living together, which at the same time are 
constituent parts of the Sicilian and other chalk marls, as ap- 
pears in the table annexed to the former memoir.on the Chalk: 
1. Dictyocha Speculum, 5. Coscinodiscus minor, 
2. Coscinodiscus Patina, 6. Actinocyclus senarius, 
3. - radiatus, 7. Gallionella sulcata. 
4. — Argus, 
These seven species, with the six already published, make up 
thirteen living species of silica-shelled Infusoria observed in the 
secondary formation; and these new and well-marked animals 
belonging to peculiar genera entitle us now to consider the pre- 
vious six not so well characterized species belonging to known 
genera, as sufficiently well determined. 
IV. General Observations on the Organic Structure of the gene- 
_rically well-characterized Infusorial Forms of the Chalk Marl. 
_ Although I have prepared, as an Appendix to these communi- 
‘cations, a more special description of the new animal forms in 
question, yet it appears to me advantageous to collect together 
a general view of the organic structure of these minute bodies, 
which have become so important from their relations. 
