4

very little fall either way. To the northeast this channel opens out into an ancient lake, and at the southwest it touches bed rock at Huntington, and then descends more rapidly.3

It will be noticed on the map that the St. Josephs, St. Mary's, and Auglaize Rivers, tributaries of the Maumee, flow in the direction of the Wabash, that the two former join at Fort Wayne and flow partly backward as the Maumee; the whole looking like a tree with its branches broken down, and hanging against its trunk. If the river was continued into the Wabash, and the water all flowed to the southwest it would form a natural looking system. It is quite within the bounds of probability that there were old overflows from the St. Lawrence drainage to the eastward of this through the Oswego River into the Mohawk, or by way of the Sorel into the Hudson, and possibly through eastern Lake Erie into the Alleghany system.

Now if the water from this region north of the Height of Land flowed over into the Mississippi drainage area at various places it would be almost certain that the Unionidæ of this system would migrate up these overflows and into the northern lakes, that in this region they would obtain a foothold and flourish, for the reason that at the time of their entrance it is quite probable that all freshwater life of this area was destroyed by the grinding and crushing of the great ice cap. It is possible that a few of the Naiades of the eastern drainage system might have survived in the St. Lawrence Valley but it is more likely that such as are now found there have since reached that region by migration from the overflows through the Mohawk and Oswego Rivers, or the Sorel. There has probably been at some time since the close of the Glacial Epoch a connection between the Hudson River and Lake Champlain, as the latter is largely peopled with Mississippi Valley Naiades. These forms, most likely, entered Lake Erie through the old Maumee Channel, or by some connection with the Upper Ohio system, passed into Lake Ontario, thence through the Oswego 3 See a paper "On the Ancient Outlet of Lake Michigan," by Prof., W. M. Davis. Pop. Science Monthly, XLVI, No. 2, p. 217. Also a paper on this old system by G. K. Gilbert, in the first volume of the Ohio Geological Survey.

and Mohawk Rivers into the Hudson, and across into Lake Champlain; or they may have gone down the St. Lawrence and up the Sorel. If by a subsidence since that time Lake Champlain has been connected with the ocean, as is now believed, the Naiads of that lake no doubt retreated up the small streams flowing into it, and returned after the elevation of the land when its waters again became fresh.

I think I am not making too sweeping an assertion when I say that all the Mississippi Valley species of Naiades that have. entered the St. Lawrence, or in fact any part of the Atlantic drainage areas, have become changed in some of their characters. As a rule, though not in every case, they have become smaller, and simpler in their outlines; the sculpture is less pronounced or is almost obliterated; in many cases the shells are thinner, the nacre has lost its brilliancy, and instead of the bright epidermis, often painted beautifully with rays or a wonderful pattern of rich greens, yellows, and olives we have mostly dull, livid, ashy or rusty reddish or brownish exteriors, and they are very often somewhat distorted. This is not, as I believe, in any great measure due to climate or colder water, for these same species are as vigorous and finely developed in parts of Wisconsin drained into the Mississippi, Minnesota and Dakota as in any part of their area; besides Anodonta edentula under the name of A. undulata, and Unio (Margaritana) marginata when found in Maryland, Virginia, and probably even south of that are so dwarfed and stunted as to be scarcely recognizable. This changing of characters has been well illustrated in a lot of Unionida recently submitted to me for examination by Prof. B. W. Everman of the U. S. Fish Commission, which was collected mostly from the Maumee basin by Dr. Philip H. Kirsch, of Columbia City, Indiana. This region lies in Lat. 41° to 411°, the most southerly part of the St. Lawrence drainage. Unio. luteolus Lam., U. subrostratus Say, U. circulus Lea, U. phaseolus Hild., U. multiplicatus Lea, U. multiradiatus Lea, and Anodonta grandis Say, are so dwarfed and stunted, and changed in color as to be scarcely recognizable, while the same species from the Wabash, from which these have no doubt all been derived, are as vigorous and finely developed as any in the Mississippi Valley.

This great change in size, form and coloring has caused students to bestow many specific names on what I believe are merely northern races or varieties of common Mississippi Valley species. Thus Anthony's Anodonta subangulata and Lea's, A. footiana, A. marryattana and A. benedictii are merely dwarfed and slightly changed forms of Say's, A. grandis. Anthony's A. subinflata is probably a form of A. corpulenta Cooper, and A. subcylindracea Lea, is the northern manifestation of Lea's well known A. ferussaciana. Say's Anodonta edentula becomes in Michigan Alasmodonta rhombica of Anthony, and further east and southeast A. undulata of Say; Lea's Unio circulus of the central Mississippi area changes in Lake Erie to the dwarf U. leibi of the same author; his U. canadensis is only an altered over U. ventricosus of the western States, and A. Gray's U. borealis is a very much changed form of the common U. luteolus, while U. hippopæus Lea, of Lake Erie is, I believe, only a stunted U. plicatus that has almost entirely lost its plications, and has assumed a dirty, reddish or olive color.

Some of these are possibly valid species; most of them would certainly be considered so, together with a number of other northern manifestations of Mississippi Valley species were it not that so many intermediate links are found.

It sometimes happens that specimens of a given species are found in the Mississippi area, growing, no doubt, under unfavorable conditions, that so closely imitate the same species found in northern waters as to be indistinguishable from it. Thus Lea has in his collection what he called Anodonta footiana, a Michigan form, from Illinois, and depauperate Unio plicatus are sometimes found in the Mississippi area that are almost exactly like U. hippopæus. And on the other hand occasionally fine specimens of Unio rectus, U. rubiginosus, Anodonta ferussaciana and A. grandis are found in the St. Lawrence drainage that are perfectly normal. Yet as a rule an expert can tell at a glance whether a specimen grew in the Mississippi area or was extra-limital.

Anodonta simpsoniana Lea, is, I believe, a good species, although it is probably an altered and dwarfed A. grandis.

It is possible that here we have an opportunity to make some kind of an estimate as to the time required in developing species and varieties among the Unionida. It is well known that the Laramie strata of the northwest, belonging perhaps to the upper cretaceous or earlier Tertiary systems contain the remains of a large number of Unios which appear to be very closely related to existing Mississippi Valley forms, and are probably their progenitors. Some of these old fossils are so much like certain recent species that they might easily be taken for them by an expert, and nearly or quite all of them can be placed in existing groups.

Yet it is more than probable that the great variety of changes that have been produced in the Mississippi Valley forms which now inhabit the St. Lawrence drainage area have taken place since the Ice Age began to draw to a close, because it is almost certain that all fluviatile and lacustine life under the ice sheet was destroyed, and that any forms closely allied to those of the Mississippi Valley now found north of the Height of Land migrated there since. It is held by most glaciologists, I believe, that the Glacial Epoch reached down probably to within from 10,000 to 20,000 years of the present. This amount of time might probably be taken as the age of these peculiar forms of St. Lawrence Mississippi Naiades.

Unio radiatus, ochraceus, cariosus, heterodon, tappanianus, and Margaritana undulata, which are found in the Atlantic drainage south of the line of the ice cap, and which are all closely related to common Mississippi Valley forms are probably older, and may have been derived from some migration made from the western to the eastern drainage at a much earlier date. At any rate I believe that all the Uniones which belong properly in the Atlantic drainage system were derived at one time and another from Mississippi Valley species; that some peculiarity of environment common to this entire region has had a tendency to dwarf them, to simplify their forms and dull their colors.

EDITOR'S TABLE.

Naturalists need not feel unkindly just now towards representative Dingley of Maine, who introduced a bill for the destruction of the seal herd of Behring Sea, which has passed the lower house of Congress. From the point of view of the lover of nature this bill appears to be an atrocity, but everything does not appear on the surface. The sole object is to destroy the commercial value of the herd, so as to put a stop to the slaughter by reckless Canadian poachers. A sufficient number will be preserved to serve as a basis of a new herd, whenever the British and Canadian Governments are ready to join hands with us in the effort to preserve it. The Dingley bill is really a plan for preserving the herd and not destroying it. The fact is that our neighbors across the border have been running up a bill of small accounts against themselves, which will in the aggregate prove burdensome to them some day if continued. It is poor policy for a weak party to make itself unpleasant, especially when the stronger party is desirous of friendly relations. Canadians and Americans are really one people, and we ought to combine not only to protect the seals, but to increase theirs numbers, and develop the industry which depends on them.

Some naturalists think it is quite the proper thing to protest that it is of absolutely no importance whether they receive credit for a discovery or not, and it is more than intimated in print from various quarters from time to time, that interest in such questions is quite inconsistent with the lofty aims of science. We must confess to having become somewhat weary of this alleged elevation of sentiment, for we find human nature to be in scientific investigators not so very different from that which is common to the rest of mankind. Under the circumstances these protestations savor of cant. The naturalist like other men must live. In order to live he must be known; hence necessity forbids that he hide his light if he have any, under a bushel. And in fact the majority of naturalists do not do so. They understand the value of honest advertising. The product of a laborer should be labelled, first for his own advantage, and second for the information of others, who know his personal equation. What we want is honest goods with honest labels, and for these no protestations of pseudomodesty, or depreciation on the part of unpractical idealists, is in place.

We are pleased to notice the excellent scientific work which is being done by the Field Museum of Chicago. The management has called