284: EVENINGS AT THE MICROSCOPE. 



are jointed independently, on rounded shelly knobs, 

 and are doubtless 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 an- 

 tennae, 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 ac- 

 tually and intensely black. Just below the eye appa- 

 rently, but considerably more towards the ventral as- 

 pect, 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 BracMonus j 

 but from their excessive tenuity, and for other reasons 

 connected with the form of the animal, they are calcu- 

 lated to tax to the utmost your perseverance and skill 

 in manipulation to resolve them. They were an enig- 

 ma to me for years. 



The great mastax is pear-shaped, pointing obliquely 

 towards the middle of the belly. This form is owing 

 to the great length of the fulcrum, and the wide cur- 

 vature of the Tnallei. The roTni are very broad, some- 

 what square at their base, fiat, but much arched longi- 

 tudinally. They open and shut vigorously, with a 

 snapping action, but are not protruded from the front ; 

 their whole interior edges come into contact. The 

 mallei are simple slender bent rods, apparently without 

 distinct articulation. During life they are thick and 

 irregular in outline, owing to their being invested with 

 dense muscles ; as is the whole upper portion of the 



