WHEEL-BEARERS 28 J^ 



arranged in groups, or bundles, of three each; one bundle 

 being set on each side of the dorsal, and one on each side 

 of the ventral aspect, at about one-fifth of the entire length 

 from the frontal points. These are all that we can ordi- 

 narily count; but I have seen more: one day, while ex- 

 amining a specimen that presented a vertical aspect to me 

 end-on, to speak familiarly the fins being all expanded, 

 I saw with perfect distinctness a seventh pair, proceeding 

 from the middle of the breast. They are flat, thin, nar- 

 row blades, of exceeding delicacy; all distinctly serrated 

 on both edges, the teeth pointing from the base outward; 

 each is strengthened by a central rib. They are jointed 

 independently, on rounded shelly knobs, and are doubt- 

 less moved by strong muscles. Under pressure, the knobs 

 and the fins are brought out with beautiful distinctness. 

 Here again we have true jointed limbs. 



On the front you may discern a pair of tiny antennas, 

 each bearing a pencil of very fine bristles. And just 

 below the level of their base, in the centre of the dorsal 

 region, you see the large eye, of a deep red hue, so deep 

 that it frequently looks as if it were actually and intensely 

 black. Just below the eye apparently, but considerably 

 more toward the ventral aspect, there is a huge mastax, 

 occupying almost half the length of the whole body. The 

 jaws are very simple in their construction, and therefore 

 very instructive, for they contain the same elements as in 

 Brachionus; but from their excessive tenuity, and for 

 other reasons connected with the form of the animal, they 

 are calculated to tax to the utmost your perseverance and 

 skill in manipulation to resolve them. They were an 

 enigma to me for years. 



The great mastax is pear-shaped, pointing obliquely 



