WORMS , 167 
Genus Planaria 
_P. grisea. Oval or elliptical in form; anterior end truncate: poste- 
rior end rounded; color yellow or gray, with a light stripe; two black 
eyes surrounded with white; length one half to three quarters of an 
ined; pea about one eighth of an inch. Found under stones between 
ide-marks. 
GEeNus Procerodes 
P. frequens. One eighth of an inch long; brown or black above, 
gray below; has two kidney-shaped eyes; active and abundant. Found 
under stones near high-water mark. 
Géinus Bdelloura 
B. rustica. Body milk-white, smooth, thin. Found on Ulva latissima 
(sea-lettuce). 
B. candida. Parasitic on the gills of the horseshoe-crab. 
Genus Fovia 
F. Warrenii. Bright red, narrow, oblong. Found on eel-grass. 
ORDER RHABDOCELIDA 
Minute, active worms found among the red seaweeds. They 
are brown in color, and are marked by one or more transverse 
white bars. 
CLASS NEMERTINEA 
The nemerteans are long, narrow, flat, smooth worms, and 
vary from one half of an inch to many feet in length. They are 
exceedingly contractile, and when alarmed can shrink to less than 
half their normal length. They are very generally distributed, 
and are to be found between tide-marks, in loose coils like a 
string, under stones on sandy and muddy shores. The very 
long species, like Lineus marinus, are solitary, but other smaller 
species are gregarious, many worms being coiled together in 
tangled masses. Some species are to be found in empty shells, 
and others live among the seaweeds. They are very slimy, the 
epidermis secreting an abundance of mucus, and they can often 
be tracked by the trail of slime they leave behind them. This 
mucus sometimes hardens, forming for some species a tubu- 
