78 Dr. H. Fol on the Family 'Tintinnodea. 
and species; and I have remarked that when the palettes are 
narrow, several large cilia are placed in a row following them. 
It is therefore very possible that the palettes are to be re- 
garded as representing a series of cilia soldered together. 
They are not rigid in any of their parts, but absolutely proto- 
plasmic and contractile throughout their whole extent. 
Hickel (LX. p. 564, and figs. 8-11) describes his genus 
Codonella as possessing similar vibratile organs; but he re- 
presents them as irregular shreds arranged upon the edge of 
a membrane. I have now observed a form very probably 
identical with that described by the above distinguished zoolo- 
gist; and I think I can assert that his interpretation is not 
correct. In this animal the vibratile lamelle are narrow; but 
they have the same general arrangement as in the other Tin- 
tinnodea, and are placed upon lines curved into portions of a 
spiral. Their lateral margins are nearly straight ; and their 
outer margin is divided into cilia. A small number of inde- 
pendent cilia complete the spiral line commenced by each of 
the undulating palettes. There is consequently nothing in 
the structure of the vibratile circlet of the Codonelle which 
justifies their separation as a distinct family from the other 
‘Tintinnodea. Moreover these palettes are much wider and 
more apparent in Cyttarocylis cassis than in Codonella. 
Hiickel represents that species as possessing in all only two 
rows of cilia; if he had seen the palettes, as he saw the much 
smaller ones of Codonella, he certainly would not have placed 
these animals in distinct families. 
I had already concluded my study of the anatomy of these 
Infusoria, and in particular of their vibratile circlet, when by 
chance I met with an article by Dr. V. Sterki (XI.)—an 
article anterior to my first memoir, but which was completely 
unknown to me. I had the pleasure of finding in it a de- 
scription entirely conformable with my corrected ideas as to 
the structure of the ciliary circlet. It is therefore to Sterki 
that belongs the most incontestable priority upon this point ; 
for Hiickel’s description cannot be regarded as_ sufficiently 
exact. 
Sterki’s description is also interesting in that it makes 
known to us a freshwater form, of which the structure is the 
same as that of the marine species, and which shows that the 
family Tintinnodea is not confined to salt water. This fact 
will assist us in judging of Sterki’s statements (VIII.) which 
I have already criticised, and especially of certain synonyms 
which have been very uselessly introducéd (XIII.). 
As I have already stated, the vibratile lines include both 
palettes and independent cilia. These cilia are placed in part 
