326 A. C. Stokes—Fresh-water Infusoria. 
coming originally from the Delaware river, and at the point where 
the Chilodon was obtained returning to it once more, during its 
passage forming in the hollows of the rocks and among the little 
heaps of stones, small comparatively still pools where the oddly 
shaped creature was oftenest captured. It of course hardly 
lives and thrives in a foaming brook, nor stems the current of 
a miniature rapid, yet it seems to prefer a locality where the 
water is not placid as a mill-pond, although it will take kindly 
to quiet surroundings. I have preserved it in a vessel on my 
table for some weeks. 
When under prolonged observation it frequently develops a 
large, postero-terminal vesicle in addition to the pulsating 
_vacuoles constantly present, occupying the entire width of the 
terminal border and contracting at long intervals. The an- 
maleule is shown in fig. 18. 
Chilodon caudatus, sp. nov. 
Body irregularly obovate, once and one-half to twice as long 
as broad, widest anteriorly, the frontal border and right-hand 
extremity of the smooth, convex dorsal region roduced in a 
short, conical, acuminate, free but motionless, spur-like prolon- 
gation ; cilia of the frontal border longest and conspicuous 
ciliated adoral groove distinct; oral aperture on the right sei 
side of the median line in the anterior body-half; contracthé 
rse 
hand 
border near the posterior extremity. Length of body st7 inch. 
Habitat. —Standing water, with Azolla Caroliniana Willd. 
In other species a common characteristic of the dorsal r en 
« 
mere 
h, bat 
That this 
