i6 



THE GUIDE TO NATURE. 



men as ever came out of Japan or 

 Switzerland, the latter place being 

 noted for the magnificent quartz found 

 there. The quartz occurred in a large 

 pocket of pegmatite which had under- 

 gone decomposition leaving the crystal 

 of quartz free. Many crystals were 

 found, some of very curious form, but 

 most of them were broken by the 

 laborers who knew nothing and cared 

 nothing about them. 



Those who wish to find specimens 

 for themselves should investigate quar- 

 ries, railroad cuts and fills, outcrops 

 of rocks and excavations of all kinds, 

 select pieces that appear odd in com- 

 position or form and apply to the near- 

 est collector or museum for information. 

 It is important that the locality of 

 specimens be known as this is often of 

 great assistance in making deter- 

 minations. 



Under the Auspices of The Aquarium Society of Philadelphia 



HERMAN T. WOLF, Editor 



The Eyes of Chinese Goldfish. 



BY HERMAN T. WOLF. 



Among the highly developed toy 

 varieties of the Chinese goldfishes there 

 are a number of breeds characterized 

 by abnormal eye development. These 

 are known as telescopic-eyed or "Tel- 

 escopes" to American and European 

 breeders and fanciers, though the 

 Chinese designation Dragon-eyes 

 would better describe these species. 



With these fishes the eyes have had 

 the principal attention of the Oriental 

 goldfish culturists, who by careful se- 

 lection and continued breeding have 

 produced monstrosities that would 

 seem incredible to those unfamiliar 

 with these highly developed fishes. 



The eyes of the common goldfish, 

 like those of the carp and other 

 cyprinidae are placed at the sides 

 of the head, separated by a wide in- 

 terorbital space, with the eye-balls 

 nearly round and the slightly convex 

 cornea flattened and directed some- 

 what forward, so that the angle of 

 vision is both in front and to the sides. 

 They are enveloped in a gelatinous 

 layer in the cavity of the orbits, which 

 permits of a considerable movement 



of the bulbus, and have brilliant dark 

 pupils and white, yellow or red irides. 

 In every respect, the eyes do not differ 

 from those of the other fishes of the 

 same order. 



Beginning with this flat form of eye 

 the Chinese breeders have produced 

 enormously large protruding eye-balls 

 which in the different breeds assume 

 the form of spheroids, segmented 

 spheres, ovoids and truncated cones 

 almost entirely projected beyond their 

 orbits. 



The cornea and crvstaline lens form 

 a smaller segment or superimposed 

 hemisphere, so that the eyes of the 

 finest specimens of the Dragon-eyed 

 goldfish protrude one-half to five-eights 

 inch from the sockets. 



Investigations have shown that the 

 eye-ball becomes greatly elongated in 

 the direction of its optic axis, the dif- 

 ference between axial and equatorial 

 diameters is as much as three milli- 

 meters in the spheroidal, and five to 

 six millimeters in the conical form 

 of eyes, constituting an extremely my- 

 opic form of eye-ball, while that of the 

 common goldfish is flat and hyper- 

 metropic. 



