PLANARIA. 117 
ovum appeared in a specimen during September. Taken among weeds 
in Redbraes Pond. 
Piate XV. 
Fic. 13. Planaria exigua. 
14. Planaria exigua, more enlarged. 
k.—PLanaria ALGA—Sea-weed Planaria.—Plate XVI. Figs. 24, 25. 
Length four lines; thickness about the eighth of the length. 
Body nearly cylindrical ; the anterior part larger than the posterior. 
Four eyes, in quadrangular arrangement, on the surface of the head. A 
proboscis protrudes from the anterior extremity. Colour siskin-green, 
tending to yellow, or to brownish. Motion very swift, with all the 
characteristics of a Planaria. 
This animal dwells among the marine Algw. 
Prats XVI. 
Fic. 24. Planaria alge, enlarged. 
25. Head, more enlarged. 
In examining the appearance of various Planariz, I have concluded 
that eyes either do not exist, or they have escaped observation. This 
may be easily accounted for, either from the colour of the parts wherein, 
if present, they are seated, or from other causes. 
a,—PLANaria FALCATA—Crescent Planaria.—Plate XVI. Figs. 26, 27. 
Length a line ; breadth a fifth or sixth of the length. Body flat- 
tened, thick, and fleshy. Two red crescents apart on the extremity of 
the head, in a circular position, but under considerable magnifiers, ap- 
pearing red streaks, sometimes consisting of one or two confluent pair 
indistinctly seen. The mouth seems in front ; and the intestine a longi- 
tudinal series of cavities, with some enlargements in their course. Crawls 
on the belly, or swims swiftly through the water. 
