2o5 CRUSTACEA. PART m. 



consists of a number of simple eyes placed under one 

 glassy cornea. It rests upon the base of a cone of mus- 

 cular fibres, which give it a movement of rotation upon 

 its centre. Its upper pair of antennse, situated below the 

 eye, spread to the right and left. In the female they have 

 numerous joints with a bristle at each joint; the lowerpair 

 of antennae are short-jointed and bristled. The mouth 

 of the Cyclops has a pair of jaws, and two pairs of foot- 

 jaws covered with bristles. The five pairs of branching 

 legs, which are fitted for swimming, are thickly beset 

 with plumose tufts. In the female the egg-sacs are 

 hung on each side of the tail (B, fig. 150) by a slender 

 tube, through which the eggs pass from the ovary within 

 the mother into the sacs where they are deposited in 

 rows, and there they remain till hatched. When the 

 larvse come into the water the sacs drop off, and the 

 young undergo various changes before coming to ma- 

 turity, as shown in fig. 150. The Cyclops swims with 

 great activity, striking the water with its antennse, feet, 

 and tail ; and the rapid movement of its foot-jaws makes 

 a whirlpool in the water which brings minute animal- 

 cules to its mouth, and even its own larvse, to be devoured. 

 Some species of the Calanus, a marine genus of the 

 one-eyed group, are eminently social. Professor Dana 

 found that the colour of those vast areas of what the 

 sailors call bloody water, met with off the coast of 

 Chili, was owing to shoals of the Calanus pontilla ; and 

 another immense area of bloody water he met with in 

 the North Pacific was owing to a vast multitude of the 

 Calanus sanguineus. Although this genus abounds 

 more in individuals in the temperate seas, the species 

 are more varied in the tropical. Those figured and 

 described in Captain Maury's works were mostly micro- 

 scopic and very beautiful ; one fished up was grey with 

 a bunch of yellow feathers at the end of its tail. The 

 egg-bags were purple, another was green marked with 



