Cerionites Dactylioides Owen. — Calvin. •">, 
lurian period where Cerionites congregated. It is probable 
Ideal section of Ceriontes (original) . 
that the skeleton was chitinous rather than calcareous. It 
was flexible enough t<> undergo extensive deformation without 
breaking, and exposed parts were frequently decomposed be- 
fore the entire structure was embedded. 
The zoological position of Cerionites is less char than 
the structure of its skeletal parts. It is scarcely probable, 
however, that the zooids that inhabited the delicate chitinous 
theca% attained the rank of Hydrozoa. It seems more prob- 
able that they were rather gigantic Protozoa. At all events I 
know of nothing to render such a view improbable. Sonic of 
our modern protozoa are about as large as the smaller individ- 
uals of Cerionites. Individuals of the genus Noctiluca are 
often a twentieth of an inch in diameter, and the gigantic 
Actinosphoeria to which I called attention in the American 
Naturalist for 1890 (Vol. 25, page 964) are even larger. Many 
of the Protozoa secrete a chitinous case or lorica. Many, as 
TJvella and Synura, live in spheroidal colonies in which the 
individuals are attached, by bands of more or less modified 
protoplasm, to the center of the sphere, and in Synura, each 
zooid is contained in a separate membranous sheath, which 
takes the form of the calices here conceived to have been pres- 
ent in Cerionites. Figures 12 and 13, plate i.ol' Kent's Manual 
of the Infusoria, representing Megosphasra planula, approxi- 
mate very closely the figure- tli.it musl be made to express my 
conception of a living colony of Cerionites. The figure ac- 
companying this paper is simply an attempt to represent <lia- 
gramatically an ideal section of such a colony. 
