REIGHARD ON BPkEEDING HABITS OF THE DOG-FISH. 133 



there by the trees to serve as homes for animals, but rather the holes 

 came there bv some accident to the tree. In the forests, trees crowd 

 each other, as they grow larger and taller, the limbs shading each other, 

 till for want of light, some of them die, or the wind or heavy sleet or the 

 falling of a neighboring tree breaks otf all or a considerable portion 

 of a limb. When the trees are sonnd and thrifty these damaged spots 

 usually grow over or close up the wound, but when the tree has nearly 

 completed its height and has sent forth numerous large limbs and has 

 gone far past its prime, these wounds heal slowly or not at all. The 

 dead limb, or the spot where it broke off, slants upward, permitting 

 water and decay to enter, till finally, a hole takes the place of the dead 

 branch, and within the tree a large cavity is often formed. Sometimes 

 two or three limbs near each other die and there may after a while appear 

 two or three holes. Many of these holes, the tree attempts to enclose, 

 year after year, and would finally succeed did not some keen rodent 

 need it for a dwelling. As the hole grows dangerously small, he gnaws 

 off the new growth, compelling the tree to keep "open doors." Squirrels 

 could use cavities entered through holes large enough for coons or hedge- 

 hogs, but they usually seek places entered through holes just about 

 large enough for the largest one of the family. In this way, they are 

 not molested by their larger enemies. Mice of the woods could use holes 

 large enough for squirrels, but they usually seek lodgings of very small 

 size. When once within hawks and owls can do them no harm. 



All of these animals are shy of one another and besides, their habits 

 are not all alike. The coon. Hying squirrel and mouse are stirring about 

 by night and remain at home asleep by day, while the gray squirrel 

 and red squirrel sleep nights and are busy at work and play by day. 



Coons store up food in the form of fat, and during cold winter curl up 

 and remain dormant for weeks together, while some squirrels lay in 

 a good store of nuts for use, when the ground is covered with snow. 



[This paper was well illustrated by numerous blocks or sections^ 

 showing the origin and formation and maintenance of homes for anim- 

 als.] 



THE BREEDING HABITS OF THE DOG-FISH, AMIA CALVA. 



BY JACOB REIGHARD, ANN ARBOR. 

 [Abstract.] 



The paper, of which this is an abstract, is a contribution towards the 

 determination of certain disputed points of fact concerning the breeding 

 habits of the dog-fish. ]>y way of preface there is given a brief statement 

 of those facts about which there is general agreement. 



In late April and early May the dog-fish seek the shallower waters 

 of our lakes and rivers and there prepare nests in which they deposit 

 their eggs. These nests are circular areas, from which all leaves and 

 stems of water plants have been removed. The bottom of the nest, 

 which is concave, is formed of the fibrous roots of water plants, less 

 often in the absence of these, of gravel, or of the water soaked leaves 



