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THE POPULAR SCIENCE MONTHLY. 



not Chinese, or nature would have been 

 more faithfully copied; nor European, for 

 the work would have been more carefully 

 finished. Professor Morse, who has resided 

 in Japan, and Mr. Tat in Basha, a Japanese, 

 aver that it is not of that origin, Mr. Basha 

 remarking that a skull is not considered a 

 fit decorative object in Japan. Large mass- 

 es of crystal have been found in the Cali- 

 fornia locality, and small skulls made of the 

 same material, measuring rarely more than 

 two inches across, have often been brought 

 from near Pachuca, in the State of Michoa- 

 can, Mexico. The skull weighs one hun- 

 dred and seventy-five and one quarter 

 ounces. The eyes are very deep hollows. 

 The line separating the upper from the 

 lower set of teeth has evidently been pro- 

 duced by a string, either held in the hand 

 or stretched across the bow, and is very 

 characteristic of Mexican work. The skill 

 of these people in making such objects has 

 been questioned, but the large masks, mir- 

 rors, and other articles of obsidian ; the ob- 

 jects of agate, and the numerous jade and 

 jadeite ornaments ; and the fact that they 

 made small skulls of rock-crystal and skulls 

 inlaid with turquoise — to the fashioning of 

 which the making of this skull was as noth- 

 ing—all indicate that they might have made 

 a large skull if a suitable stone came into 

 their possession. Since they procured their 

 turquoise from Los Ccrilles, New Mexico, 

 why should we doubt that they were ac- 

 quainted with the California locality for 

 rock-crystal? 



The Nest of the « Pnrsc-Web » Spi- 

 der. — Among the natural-history papers 

 read in the British Association was one by 

 Dr. H. C. McCook, describing the nesting 

 habits of the spider ^<j/;jms niger of Florida, 

 a species which it has been found was first 

 observed and figured, as the " purse-web 

 spider," by John Abbott, in 1792. The 

 nesta of the Atypus are silken tubes of close 

 texture and various lengths and sizes, 

 which are spun against the bark of trees 

 in nearly equal proportions above and below 

 the surface of the ground. Some of the 

 tubes are from twelve to fourteen inches 

 long, and from one half inch to three quar- 

 ters inch in diameter ; others — the nests of 

 the young — are a few inches long and of 



the thickness of a pipe-.stem. The inside 

 of the nests is white and clean ; the outside 

 is weather-stained and covered with sand. 

 In spinning these tubes the spider first 

 stretches a series of straight threads from 

 a point on the bark about an inch and a 

 half above the ground. These lines are 

 more or less approximated, and present the 

 appearance of a rough framework for the 

 tube. Upon them the architect places a 

 thickening of spinning-work, which is beat- 

 en down and spread over by the long spin- 

 ners, the process resembling more that of a 

 plasterer than of a weaver. The work is 

 done in small sections, until the original 

 frame is quite covered in. The lengthening 

 of the tube is accomplished by adding to 

 the original section until the desired length 

 is attained. The new-made tubes were 

 found covered on the outside with sand. 

 The spiders were not seen in the act of 

 sanding their nests, but a similar habit in 

 Atypus piccus of England has been ob- 

 served and described by Mr. F. Enock, 

 who has discovered that the sand is forced 

 through the texture of the web from the in- 

 side. The idea of mimicry has been ad- 

 vanced in connection with this nest-sanding. 

 Certainly the tube does closely resemble 

 the tree to which it is attached. But Mr. 

 Enock's observations indicate that the spi- 

 der has taken a convenient way of getting 

 rid of the sand brought up by its mandibles 

 from the excavations of its burrow below 

 the surface. 



Insects resembling Minerals.— Mr. Ed- 

 ward B. Poulton, discussing the resem- 

 blances which certain inscct-pupaj seem to 

 bear in color to the surface on which they 

 are found, thinks it probable that the gilded 

 pupae of Vanessidce (butterflies) resemble 

 glittering minerals, like mica, which is very 

 common in many places. Their shape is 

 very angular, and like that of minerals. 

 Conversely, the gray pupa; resemble gray 

 and weathered rock-surfaces ; and the two 

 conditions of rock would themselves act as 

 a stimulus for the production of pupa; of 

 corresponding color. The power was prob- 

 ably gained in some dry, hot country where 

 mineral surfaces do not weather quickly. 

 Once formed, it may be used for other pur- 

 poses, and in certain species probably con- 



