124 EVENINGS AT THE MICROSCOPE 



you have never submitted them to half an hour's micro- 

 scopical examination. I have caught one with a spoon, 

 and pat it into this narrow glass trough of water that it 

 may rest conveniently on the stage. 



We will take a cursory glance at its entire person. 

 Here is a flat, roundish head, a great globose, swollen 

 thorax, and a long, slender, many -join ted body, ending 

 in a curious fork. But all is curious: the head, with its 

 horny transparency; its pair of rod-like antennae, covered 

 with minute points; its two black eye- patches; and its 

 jaws, beset with strong, curved hairs, set in radiating rows, 

 and, ever and anon, working to and fro with the most 

 rapid vibrations: the thorax, so transparent, with its am- 

 ber-like clearness, that you can discern the dorsal vessel, 

 which contains the blood, ever dilating and collapsing with 

 the most beautiful regularity; and, beneath this, the gul- 

 let, through which, now and then, descends a dark pellet 

 of food, to join the mass already lodged in the stomach 

 further down a result, by the way, that explains that 

 incessant vibration and pumping motion of the mouth- 

 organs, which thus evidently are engaged in collecting 

 food from the water; though, even with this power, we 

 can see no solid matter taken in, till we discern it agglom- 

 erated in the swallowed pellets: the body, or abdomen, 

 with its ten joints, all (with a slight exception) the coun- 

 terparts of each other; and each carrying its own dilata- 

 tion of the dorsal vessel, and its own portion of the long 

 and well-filled intestinal canal: all these, I say, are very 

 interesting and curious to observe; especially when we 

 select, as I have done, a young individual for examination; 

 since the tissues then possess a translucency which is essen- 

 tial to our seeing with distinctness anything of the internal 



