648 Wisconsin Academy of Sciences, Arts, and Letters. 
senting the rudiments of the normal additional teeth. The manu¬ 
brium is a straight rod, very slightly larger at the base. Two 
straight rods, expanded at their dorsal ends into triangular plates, 
pass transversely across the mastax to the dorsal ends of the 
rami; they are imbedded in the walls of the mastax and support 
them during the pumping action. Two well developed ventral 
salivary glands are present; the right gland is considerably larger 
than the left. 
The oesophagus is unusually long and slender. The gastric 
glands are small and rounded. The stomach and intestine are not 
distinctly separated. The ovary is large and ovate in outline. A 
normal bladder is present. The foot glands are long and slightly 
club-shaped. 
The ganglion is small and saccate. The retrocerebral organ 
consists of a small, clear sac and two subcerebral glands, as large 
as the sac. Neither glands nor sac contain bacteroids. The eye- 
spot is large and at the posterior end of the ganglion; two pig¬ 
ment spots or accessory eye-spots are situated on the corona, im¬ 
mediately under the integument, near the openings of the ducts 
of the retrocerebral organ. 
Total length 350-400/a ; toes 35-40 /a ; trophi 50/a. 
Eothinia elongata is not very common; we have collected it in 
small numbers at Lac Vieux Desert, Vilas County, Three Lakes, 
Oneida County, Wisconsin, and at Four-mile Run, in Virginia, 
near Washington. 
It is necessary to create a new genus for this species, as the 
mastax is entirely different from the normal Eosphora- type; the 
great dissimilarity in external form between Eothinia elongata 
and Sphyrias lofuana prevents its being referred to the latter 
genus. 
Notes on Collecting and Mounting Rotifers 
The methods for collecting the limnetic rotifers living away 
from plants in the larger bodies of water are very simple; either 
a throwing or a dip net will do. It is necessary to have it made 
of material sufficiently thin to allow the water to pass through, 
and at the same time fine enough to retain the rotifers; these con¬ 
ditions are readily fulfilled by several varieties of moderate priced 
cotton goods, india linen, nainsook, lawn, etc. A convenient size 
for the net is a diameter of about six inches with a length of ten 
