482 THE POPULAR SCIENCE MONTHLY. 



glisteniug with a greenisli luster, jet-black skins, and other feat- 

 ures like those of men. The tomb had become immensely large, 

 and had taken the shape of a minaret towering into the clouds. 

 It then began to shake, and Sheik Adi in his fright overturned a 

 water-jar that was standing by his side ; and the aj^parition, 

 which had turned into the shape of a handsome boy with a pea- 

 cock's tail, exhorted him : " Do not be afraid ; the minaret, in- 

 deed, will fall and destroy the earth, but you and those who hear 

 your word shall not be harmed, and shall rule over the ruins. I 

 am Melek-Taus, and have chosen you to publish the religion of 

 the truth over the earth." This said, he took Sheik Adi's spirit 

 with him into heaven, where it stayed for seven years, receiving 

 instruction in all truths, while the body of the saint remained 

 asleep by the tomb of Abu Rish. When his soul returned to it 

 from the sky, the water had not yet run out of the overturned 

 jar. — Translated for the Popular Science Monthly from Das 

 Ausland. 



THE DANCE OF THE LADY CRAB. 



By T. H. morgan. 



ABOUT the 12th of September, 1888, there was brought into 

 the laboratory of the United States Fish Commission a male 

 specimen of the lady crab {Platyonychus ocellatus), which was 

 placed in an aquarium with a female crab of the same species. 

 During the evening of the 13th, while sketching some hermit- 

 crabs which had previously been placed in the same tank, I was 

 attracted by the movements of the male Platyonychus. Without 

 apparent cause he was seen to rise upon the third and fourth 

 pairs of legs ; his large chelae were thrown above his head with 

 the claws open and their points touching in the middle line ; his 

 fifth pair of feet were held horizontally behind, and his body per- 

 pendicular to the floor of the aquarium, or at right angles to the 

 normal position, as shown in the accompanying figure. The post- 

 ure was ludicrous, and, when in this position he began slowly to 

 gyrate, his movements and attitude were the cause of much merri- 

 ment upon the part of the spectators. At times he balanced on 

 two legs of one side, again on two legs of opposite sides. Now he 

 advances slowly and majestically, and now he wheels in circles in 

 the sand on the floor of the aquarium, and now for a few moments 

 he stands as if transfixed in this unnatural position. An electric 

 light hung above and to one side of the water, which suggested 

 the possibility that it might be the exciting cause. It was turned 

 out, and still the dance went on, and the joy was unconfined. At 



