240 EVENINGS AT THE MICROSCOPE 



ous colors, as red, green, or brown in those species which 

 are active by daylight, while it is black at the back of the 

 eye. The nocturnal species have no dark pigments, but 

 are furnished with a curtain (tapetum), which reflects a 

 brilliant metallic lustre, and makes the eyes of these Spi- 

 ders glare in the twilight, like those of cats. 



It will be interesting to compare with this range of 

 eyes the same organs in a kindred animal, the common 

 Harvestman (Phalangium cornutum). Here in the centre 

 of the cephalo- thorax rises a short pillar, which is crowned 

 with two rows of conical points, with polished black tips. 

 On each side of the pillar is a large black eye, hemispher- 

 ical in form, and brilliantly glossy, exactly resembling, 

 indeed, those which we have just examined. There are, 

 however, only this single pair which thus look out later- 

 ally, exactly like the eyes of Birds. There is, indeed, a 

 speck on each side of the thorax, considerably removed 

 from the eye-pillar, just above the origin of the first pair 

 of legs, which has been mistaken for an eye; but it is 

 truly a spiracle, or breathing hole. 



There are many other points of interest about this Har- 

 vestman, such as the conical spines which stud the head, 

 body, and limbs; the multitude of small bead-like joints 

 into which the foot (tarsus) is divided; and in particular 

 the hammer-like form of the modified antenna, which bend 

 abruptly downward, and have pincer-tips. These are highly 

 curious, and you may examine them at your leisure; but 

 for the present we will return to our Spiders. 



Ever since those mythic times when Arachne con- 

 tended with Minerva for supremacy in needle-work, and 

 was changed, for her pains, into a spider, our little spin- 

 ners have been famous (Spider = Grer. Spinne) for their 



