ANNELIDES. 



93 



No. XVI. 



desirable to have atiy addition to man's weapons fit for war, it 

 might furnish the model of a new kind as for- 

 midable as any we yet possess. The bayonet 

 part of the bristle is, in fact, also a sheath, 

 which encloses another weapon that is only ex- 

 posed when the scabbard has been lost. When 

 we separate the bayonet from the shaft, we, at 

 the same time, force from its interior a horny 

 stylette (fig. 26 h), — the true termination of the 

 bristle, — so that the place where the bayonet is 

 attached is not obtuse or inflated, as it seems to 

 be, but is, on the contrary, tipped with a needle- 

 like point, ready to become a good defensive 

 instrument when the enclosing appendage has 

 been lost or expended. 



The Aphrodita hystrix has, in the dorsal 

 branch of its feet, bristles of a very different 

 composition, and which may be described as 

 lances*. It is easy enough to form a notion of 

 their form by recalling to ourselves the figure of 

 a lance, or of a long pike barbed on the edges 

 near the apex (No. XVII. fig. 28) ; and let it be 

 remembered that>the lances of the Annelid are 

 so small that a considerable magnifier is re- 

 quired to discover their workmanship, which 

 excels in finish the finest instrument manufac- 

 tured by the skill and patience of the most 

 expert artificer ; for, unlike man's productions, 

 this tiny lance " not only bears the microscopic glance, but the more 

 minutely it is examined, the more fully its exquisite organization is 

 disclosedf." A great number of these bristles garnish the extre- 

 mity of each foot, and as they are stiff and serried, they form a hedge 

 of spears round the body of the worm, placing it, as it were, within a 

 square of pointed pikes threatening at all points;]!. 



Associated with the lance-bristles, there are found, in the same 

 Aphrodite, numerous others terminating in a sort of knob (fig. 29). 

 When this knob is opened longitudinally, there is found within it a 

 barbed lance, in all respects resembling those just described (fig. 30). 

 So the lance-bristles appear to be bristles which have been deprived 

 of their sheaths. The sheath secures only the barbed point, and 

 each barbule has its own little separate sheath or furrow, as may be 

 seen on separating the valves of the main sheath. Then, on in- 

 spection of the inner side of either valve, it is not difficult to discover 



* "Fleches" is the term used by Audouin and Milne-Edwards; but as the 

 weapon is thrust, and not shot, 1 have preferred lances to arrows. 



t See the Chapter LI. — " Art and Nature compared," — in ' Baker's Microscope 

 made easy,' p. 292, 3rd edit. Lond. 1744. 



X In reference to Aphrodita hystrix, Mr. Alder writes me : " They are very in- 

 convenient neighbours in a bottle, as their sharp spines stick into everything ; and 

 in examining the contents of a dredge where they are, they pierce the fingers, 

 breaking in and becoming very painful." — Letter, Feb. 17, 1854. 



