1884.J NATURAL SCIENCES OP PHILADELPHIA. 151 



June 3. 

 Mr. Edward Potts in the chair. 

 Fifteen persons present. 



A paper, entitled " On the Mutual Relations of the Hemi- 

 branchiate Fishes," by Theodore Gill, was presented for publica- 

 tion. 



Opposite Leaves in Salix nigra. — At the meeting of the Botanical 

 Section on June 2, Mr. Thomas Meehan remarked that few 

 botanists would expect to find opposite leaves in Salix; but in S. 

 nigra Marshall, they appear at a certain stage of growth, which 

 has much significance. This species is of that section which has 

 the flower cotetaneous with the leaves ; that is to sa3', instead of 

 the aments being sessile they terminate short branches. They 

 are, however, not absolutely terminal, but appear so by the sup- 

 pression for a time of the terminal bud. In the case of the female 

 ament this terminal bud usually starts to grow very soon after 

 the flowers mature, and forms a second growth, when the fertile 

 catkin or raceme of fruit, becomes lateral. It is the first pair of 

 leaves on this second growth that is opposite — all the rest are 

 alternate as in the normal character of the genus. The leaves are 

 so uniformly opposite under these circumstances, that there must 

 be some general law determining the condition, which has not yet 

 been developed. 



June 10. 

 Mr. Geo. W. Tryon, Jr., in the chair. 

 Fourteen persons present. 



A paper, entitled " On the Anacanthine Fishes," by Theodore 

 Gill, was presented for publication. 



June 17. 

 Rev. H. C. McCooK, D. D., "Vice-President, in the chair. 

 Thirteen persons present. 



A Spider that makes a spherical Mud-daub Cocoon. — The Rev. 

 Dr. H. C. McCooK said that in November, 1883, he received from 

 Mr. F. M. Webster, Assistant State Entomologist of Illinois, two 

 globular nodules of earth, about the size of a grape, which were 

 thought to be the cocoons of a spider. Similar balls had often 

 been found attached, by a slender thread or cord of silk, to the 

 underside of boards laid down on the ground. From some of 



