departme;nt op marine biology. 149 



ates faster than a large one. Morgan's results in the regeneration of the 

 earthworm, fish, and salamander are substantiated in the medusa, and thus 

 it appears that it is a general law that the deeper the level of the cut the 

 faster the rate of regeneration. The degree of injury has little or no effect 

 upon the rate of regeneration, and it makes no appreciable difference whether 

 the regenerating tissue be pulsating or at rest. 



One of the most suggestive of Professor Stockard's results is his discovery 

 that the regenerating tissue grows, if necessary, at the expense of the body 

 itself, and if starved the old body actually decreases in size to provide nutri- 

 ment for the rapidly proliferating cells of the regenerating tissue. He shows 

 that in its remarkable ability to absorb nutriment regenerating tissue resem- 

 bles cancer and other malignant tumors. He finds that CaCl, and NaCl tend 

 to retard regeneration, as do also strong solutions of KCl, but weak solu- 

 tions of KCl accelerate the process. 



Professor Stockard extends his studies on regeneration to include two 

 species of brittle-stars (Ophiocoiiia), and here again he finds that the nearer 

 the cut is made to the margin of the central disk the faster will the arm 

 regenerate, but removing more than one aiTn does not increase the rate of 

 regeneration. Hence the animal with the greater number of removed parts 

 does not regenerate each part at a faster rate than the animal with the lesser 

 number of removed parts. 



Another of Professor Stockard's researches was upon the habits of the 

 walking-stick insect Aplopiis, which lives upon the bay cedar {Stiriana) 

 bushes at Tortugas and bears a striking resemblance to a stick of the bush 

 itself, while its eggs resemble the seeds of the same bush. Professor Stockard 

 finds that the habits of the insect accord perfectly with and enhance the value 

 of its protective coloration. The insect is active only at night, or in dark- 

 ness; and in daylight they may be piled one on top of another, remaining 

 motionless in any attitude. 



In another research, Professor Stockard studied the regeneration of the 

 chelae in Alpheus. It is well known that if the large chela of Alpheus be cut 

 off, the small chela changes into a large one at the next molt. Professor 

 Stockard finds, however, that if the large chela be removed, and at the same 

 time some legs of the opposite side of the body (except the small chela) be 

 cut off, the small chela does not change into a large one and the animal 

 acquires two equally developed small chelae at the next molt. Thus the 

 tendency toward a reversal is checked. Stockard also checked this tendency 

 in two other ways which are described in his preliminary report, herewith 

 published. 



Prof. David H. Tennent has discovered that if the two sea-urchins Hippo- 

 no'e and Toxopneustes be reciprocally crossed in natural sea-water or in sea- 

 water rendered decidedly alkaline with NaOH, the Hipponoe parent is 



