218 EVENINGS AT THE MICROSCOPE. 



their webs, from the particles of dust and other ex- 

 traneous matter which are continually cleaving to them. 



There are Spiders in the sea also. I can show you one 

 which is sufficiently common on the southern shores, 

 sprawling and crawling sluggishly among the filamentous 

 sea-weeds and branching flexible zoophytes. Here it is, 

 Nymphon by name. 



Its most prominent characteristic is the exceeding slen- 

 derness of all its parts, but especially its eight legs, which 

 are greatly lengthened, each comprising eight joints, and 

 no thicker than the finest thread. On the other hand, 

 the body is reduced to a minimum ; the abdomen, which 

 in the Spiders and Harvestmen of the land is so bulky as 

 to constitute the chief volume of the animal, is here so 

 minute that you will have some difficulty in finding it 

 at all ; it is, in fact, that tiny atom of a point that 

 projects between the hindmost pair of limbs. The 

 thorax, indeed, is a little more developed ; but even 

 this has scarcely any appreciable breadth or thickness, 

 being little more than the extended line formed by 

 the successive points of origin of the limbs. 



The head, however, is distinct and well furnished. It 

 is crowned with a short column, much as in the Harvest- 

 man, on the summit of which are placed four black eyes, 

 set in square ; these, under the magnifying power which 

 we are applying to them, gleam like diamonds, the light 

 being highly refracted through them. It is the high 

 refractive power of these eyes, as of those which we 

 have lately been examining, which makes them appear 

 black ; for, as I have explained, they are really trans- 

 parent lenses, covered with polished cornea?, and 

 furnished with the other essentials requisite for the 

 transmission of the rays of light to the optic nerve, or, 

 as in this case, direct to the brain. 



In front, you see, the head projects into a stout oval or 

 cylindrical proboscis, terminating in a small mouth and 



