clxxx Journal of Comparative Neurology. 



visible skipping-rope. They would keep up this play for several min- 

 utes and then resume feeding or quietly remain at rest. This rotifer 

 goes through another performance which I also believe to be simply a 

 pastime. Its tail is armed with a double hook or forceps. It attaches 

 itself to a piece of alga or other substance by this forceps, and then 

 moves its bodv up and down in the water several minutes at a time." 

 " Swarms of Diptera may be seen on any bright day dancing in. the 

 sunlight. Naturalists have therefore considered this swarming to be a 

 mating of the two sexes. This is not the case, however, in many in- 

 stances. On numerous occasions, and at different seasons of the year, 

 I have captured dozens of these insects in my net and have examined 

 them microscopically. I found them all to be unimpregnated females; 

 I have never yet discovered a male among them. In some of the 

 Diptera the males emerge from the pupa state after the females ; I 

 therefore believe that the females await the presence of the males, 

 and, while waiting, pass the time away in aerial gambols." " Some 

 time ago I witnessed a bit of malicious sport, in which the participants 

 were fleas. I was observing a Pulex sleeping beneath the short hairs 

 of a dog's axilla. My lense was a good one and I could clearly make 

 out the body and limbs of the little sleeper. Suddenly there appeared 

 another flea, which stopped short as soon as she discovered her 

 sleeping comrade. She remained quiet for several seconds and 

 then nimbly bounded on the others back. Clasping her body with 

 her hind legs, she began vigorously ' to touzle the hair' of her sur- 

 prised sister. She then sprang away into the thicker hair, closely pur- 

 sued by the thoroughly aroused and evidently angry victim of her 

 sport." The sport of ants and other animals is alluded to and the 

 author expresses the opinion " that every living creature, at some pe- 

 riod of its existence, has its moments of relaxation from the cares of life 

 when it enjoys the gratification of true psychical amusement." 



The Annual of the Universal Medical Sciences. 1 



The issue of the Annual for 1894 is fully up to the high stand- 

 ard set by the earlier issues. Written for the practical needs of the 

 busy physician who desires to keep abreast of the times, the principle 

 of selection must obviously be immediate practical utility ; and we 

 are pleased to notice that a few carefully selected articles on morpho- 



'Charles E. Sajous, Editor-in-Chief. Published by The F. A. Davis Co. 

 Philadelphia, 1894, 5 vols. 



