470 Kurtz and Huntington — Diamonds in Meteoric 



another individual. The biramous character of the entire 

 series of thoracic legs is very evident, as is also the distinction 

 between the crawling and swimming members. Figure 2 

 shows the right second and third legs of the free thoracic seg- 

 ments. In figure 3, the upper exopodite is represented with- 

 out setse, so as to bring out the structure in greater detail. 

 On the lower leg the setse are shown. 



It is not proposed at this time to make any extensive com- 

 parisons or homologies with other groups of Crustacea, as the 

 appendages of the head and pygidium still require further 

 description and illustration, and will be the subject of a future 

 contribution. It is evident, however, that the relations of the 

 trilobites are with the Entomostraca and M alacostraca. More- 

 over, like the Leptostraca (Nebalia), the Trilobita probably 

 constitute an intermediate type having affinities with the Ento- 

 mostraca chiefly in the irregular segmentation, and with the 

 lower forms of the Malacostraca (as the Schizopoda, Cumacea, 

 and Anisopoda) in the detailed structure of the limbs. 



Art, LXIII. — On the Diamond in the Canon Diablo Meteoric 

 Iron and on the hardness of Carborundum ; by George 

 Frederick Kunz and Oliver W. Huntington, Ph.D. 



The discovery of diamonds in the Canon Diablo meteoric 

 iron was first announced by Dr. A. E. Foote in this Journal 

 for July, 1891 (vol. xlii, pp. 413-417). He found in the cut- 

 ting of this meteorite that it was of extraordinary hardness, a 

 day and a half of time being consumed and chisels destroyed 

 in the process of removing a section. In cutting, the chisels 

 had fortunately gone through a crevice filled with small cavi- 

 ties. The emery wheel used to polish this surface was ruined, 

 and on examination the exposed cavities were found to contain 

 hard particles which cut through polished corundum as easily 

 as a knife cuts gypsum. The grains exposed were small and 

 black, and Professor Geo. A. Koenig pronounced them dia- 

 monds because of their hardness and indifference to chemical 

 agents. The extreme hardness was subsequently verified by 

 one of us (G. F. Kunz), who carefully examined the type 

 specimen. 



On July 8, 1892 (Science, p. 15), Dr. Oliver Whipple 

 Huntington gave the result of his experiments with this re- 

 markably interesting Canon Diablo iron. Taking one hun- 

 dred grams of the iron he placed it in a perforated platinum 

 cone suspended in a platinum bowl filled with acid, the cone 



