1. UPWARD MOVEMENT OF ONE PER CENT. EOSINE WATER THROUGH CUT STEMS..

(No. 9). This vine was 215 centimeters long and bore a number of small leaves and 17 large ones, 10 of which averaged 20 cm. in breadth. March 21, 2:30 p.m. The stem near the earth was cut under water and put at once into 1 per cent. eosine water.1 2:43 p.m. The stain is now distinct in all of the principal veins of a leaf only 15 cm. from the end of the stem, i. e., it has passed up the stem a distance of two meters in less than 13 minutes, probably in 10 to 12 minutes. 2:47 p. m. The red stain is now distinct in the veins of the small undeveloped uppermost leaves of the stem. 3:25 p. m. Slight droop of the foliage, but much less than in No. 10 (a similar vine in 10 per cent. eosine water). Foliage decidedly less red than that of No. 10. 4:35 p. m. Leaves drooping very decidedly. The leaves of No. 10 are flabbier and redder, but much less fluid has passed up the stem. 5:10 p.m. About 21 cc. of the eosine water has passed up the stem in 2 hours and 40 minutes. March 22, noon. Leaves, tendrils and surface of the young fruits reddish. The stain does not make its way readily into the coiled tips of the tendrils. Many of the leaves are dry shriveled, so that they crackle on touch. Stem not shriveled. Most of the petioles are still turgid and but little stain is visible in them, except in a few toward the top of the vine. 4:00 p.m. Not nearly so red as No. 10. Stem quite green and not noticeably shriveled. The stem of No. 10 in the 10 per cent. eosine has shriveled decidedly to-day. March 23, 12:25 p.m. About 10 cc. of the stain has passed up the stem since last night. 4:30 p.m. About 10 cc: of the stain has gone up the stem since the last record. March 25, 12:30 p.m. About 20 cc. of the stain has passed up the stem since the last record. Most of the leaves are crisp dry, but the terminal ones are still moist, although shriveled and soft like old rags, the parenchyma being yellow and the veins bright red. Most of the petioles are bright red, and all of them are limp and hang straight down; the stem has shriveled and become reddish, except the

'Distilled water containing Dr. Grübler's "Eosine Soluble in water."

submerged part, which has kept its turgor and resists diffuse staining better than the parts in the air. The plant is dead. March 26, 2:40 p. m. About 12 cc. of the eosine has passed up the stem since yesterday p. m.

In this plant over 40 cc. of the eosine water passed up the stem during the first 24 hours, and in the next four days an additional 45 cc., part of which after the plant was dead.

Vine No. 1 which was 188 centimeters long, also took up the eosine water after it was dead. This absorption of the stain continued long after the leaves had become dry-shriveled, and did not entirely cease until all parts of the bright red stem became bone-dry. This vine was under observation 14 days, during which time about 150 cc. of 1 per cent eosine water passed up the stem, only 57 cc. of which went up during the first 49 hours.

(No. 25). This was a young vine, measuring 100 centimeters above the cut surface. It bore 17 leaves, the largest 6 averaging 13 cm. in breadth. March 28, 11:56 a. m. The stem was cut under water and put at once into an alkaline eosine water, made by putting 1 gr. eosine into 100 cc. of caustic soda (the solution stood in the laboratory over night and became darker colored). 12:01 p.m. The red stain is distinctly visible in the veins of all the leaves, even the uppermost ones, i. e., it has gone straight up a distance of one metre in 5 minutes. It is sunny and windy, and transpiration is active. The dry bulb registers 22° C.; the wet bulb 17.3° C. 12:10 p.m. The foliage begins to droop. 12:40 p. m. Foliage wilting very badly. 2:10 p. m. About 5 cc. of the stain have passed up the stem. The lower leaves have begun to crisp at the margin. March 29, 2:30 p.m. About 7 cc. of the stain have passed up the stem since the last record. The blades of the leaves are crisp and the petioles are bright red. March 30. Fluid quite dark; an additional 4 to 5 cc. has gone up the stem. Stem and petioles much brighter red than yesterday. April 3, 11 a. m. The entire stem and all of the petioles have become extremely bright red, the eosine water (20 cc. of it) having continued to pass up the dead stem since the last record. The leaves appear to have taken up no stain since March 29.

They are not now crisp, but feel limp like old rags. The veins are bright red, but the parenchyma is yellowish-white. The surface of the stem feels moist and stains the fingers red when rubbed.

Similiar results were obtained with a 1 per cent. solution of sodium chloride containing 1 per cent. eosine. Acidulated waters (1 per cent. citric acid and 1 per cent. hydrochloric acid) also passed up the cut stems rapidly and in large quantity, and after the stems were dead. The 1 per cent. hydrochloric acid proved much more poisonous to the plant than did the 1 per cent. citric acid. Similar experiments were made with hydrant water. In the latter, after a few days, the plants reduced their foliage to a minimum, and then lived on for many days, i. e., in case of a plant used for comparison with No. 1, until long after the latter was dead and dry.

To sum up the results of these experiments, of which the preceding are only examples, we have the following propositions:

(1). The rate of movement of the water current in cucumber stems during active transpiration is at least 10 to 12 meters an hour. (2). Absorption of water and transpiration continues in dead stems for some time, i. e., until they have become dry. (3). Large quantities of fluid passed through the cut stems during the first few days. (4). When the cut stems were plunged into water tinged with eosine, sufficient of this stain was taken up to color all the tissues of the plant bright red, including parenchyma, sclerenchyma, collenchyma and epidermis; the first parts to show the stain being the spiral vessels.

(To be Continued.)

ON THE MISSISSIPPI VALLEY UNIONIDÆ FOUND IN THE ST. LAWRENCE AND ATLANTIC

DRAINAGE AREAS.

BY CHAS. T. SIMPSON.

The entire Mississippi drainage area is peopled by a peculiar Unione Fauna.1

The species are exceedingly numerous. and many of them attain great size, or become very solid at maturity. A large number are characterized by strong sculpture in the form of knobes, pustules or plications, or by striking outlines, and the species in general are more richly colored externally or internally than those of any other part of the globe.

The Atlantic drainage area, including a considerable part of the St. Lawrence River system, is occupied by a very different Naiad fauna. As a rule the species are moderate in size and conform nearly to the ordinary oval or oblong-oval Unione type; they are of light structure, without sculpture or strong angularities and lobes, and are plain colored in nacre and epidermis.

The dividing line between these two Unione faunas is not directly on the Height of Land, which separates the St. Lawrence and some of the other Atlantic drainage systems from that of the Mississippi, but it is considerably to the northward and north-eastward of it.2

To the westward the Red River of the north, the Saskatchewan and Mackenzie are largely inhabited by Mississippi Valley Uniones, and they are found abundantly in all the great lakes, the southern peninsula of Michigan, the streams in Wisconsin, Indiana and Ohio that drain into these lakes, and well up into Eastern Canada, Lake Champlain and

1 See paper by the writer "On the Relationships and Distribution of the North American Unionida" in Am. Naturalist, XXVII, p, 353.

* This matter will be discussed in a paper by the writer, which will soon be published in the Proc. N. S. National Museum "On the Classification and Distribution of the Naiades,"

the Hudson River, in some places mingling with the forms belonging to the Atlantic drainage area proper, in others occupying the waters exclusively.

I think we may safely take it for granted that the only way in which the Mississippi Valley Unionidæ could have entered these northern and north-eastern river systems was by migrating along connecting fresh water. As there is no such connection to-day between these systems the question as to how they reached their present distribution becomes an extremely interesting one.

If the theory of the Ice Age as held by most glacialists is a true one I think it will fully explain the present remarkable distribution of these extra-limital Mississippi Valley Naiades. And at the same time I believe the evidence of these fresh water mussels is strongly corroborative of the glacial theory. It is held that at the close of the Ice Age a great cap of ice of immense thickness covered North America east of the Rocky Mountains, down to about Latitude 40°. That with the coming on of warm weather it gradually melted away at its southern extremity, and that when this thawing was continued north of the height of land great lakes were formed whose southern shores were the slope of the land which raised towards the south, and whose northern borders were the slowly dissolving wall of ice. On account of the ice to the northward this water could only drain into the Mississippi system, or to the Southeastward, and several old channels are found through which it is believed that it flowed. One of these is the Red River of the North, which almost connects by means of Traverse Lake at its head with Big Stone Lake at the head of the Minnesota River. There is still a broad channel near the western end of Lake Superior which connects with the St. Croix River, and at Chicago there was no doubt an overflow from Lake Michigan into the Des Plaines River, and Lake Erie is believed to have had its outlet into the Wabash through the Maumee which nearly connects with it. The two streams are connected over a very flat country by an old channel not less than a mile and a half wide, and having an average depth of 20 feet. For 25 miles this character continues, and there is