Dr. H. Fol on the Family 'Tintinnodea. 87 
plausible reason for reserving this family name for a hypo- 
thetical type founded upon defective descriptions. This, 
however, is what has been done by Saville Kent (XIII. 
p. 624), who gives the name of Dictyocystide to the Tintin- 
nodea, and suppresses the former name because he has not 
found animals to which he could apply it. The Dictyo- 
cystide of Saville Kent are simply a synonym of the Tintin- 
nodea of Claparéde and Lachmann, a synonym which we may 
simply set on one side, since the priority belongs incontestably 
to the name that I have adopted. 
This applies also to the genus Petalotricha, which Saville 
Kent seeks to substitute for the name of Tintinnus. Here, 
again, he seems to reserve this latter name for hypothetical 
animals. It would be superfluous to combat a prejudice ; it 
suffices to demonstrate it. 
The families Dictyocystide and Codonellide, as Hiickel has 
established them, have a better claim on our attention; for 
these are not simple synonyms. ‘These families are founded 
upon anatomical differences; and it remains only to learn 
whether these differences are real or whether they are not 
rather based upon insufficient observations. I pronounce 
without any hesitation for the latter alternative. The pre- 
ceding pages show that the organization of our Infusoria does 
not vary much, and that even in the arrangement of the peri- 
stome, upon which Hickel founded his distinctions, there 
does not exist any difference sufficient to justify their separa- 
tion into several families. The genus Codonella is the only 
one that presents well-marked characters, not in its peristome, 
but in the structure of its test and in the presence of two 
nuclei at the hinder part of its body. Have these differences 
more than a generic value? I do not think so, and I regard 
all the Tintinnodea known at the present day as forming a 
single tribe and a single family. As regards the position of 
this family relatively to the peritrichous Infusoria I have 
already given my opinion, an opinion which my later researches 
have only confirmed and still more strongly accentuated. 
EXPLANATION OF PLATE IV. 
Fig. 7. Tintinnus ampulla, treated with perchloride of iron and gallic acid 
and mounted in Canada balsam. x 420. 
Fig.8. Cyttarocylis cistellula, the test treated with perchloride of iron and 
gallic acid and preserved in balsam. x 420. 
Fig. 9. Dictyocysta templum, the test treated like the preceding. x 420, 
Fig. 10. Upper portion of the test, seen in optical section; treated with 
perchloride of iron, gallic acid, and Canada balsam. x 420. 
