APHRODITA. 105 



colour. The bristles are not extruded from the extremity, but from 

 a sort of projection beneath it : the two upper ones are fihform, 

 obtuse, and of a dark brown colour ; the two next are most protruded, 

 smooth, paler, with a sharp slightly curved point ; and the under 

 one is short and acutely pointed like a dagger. This branch then is 

 armed with no less than four different sorts of bristles, calculated 

 both to cut and lacerate and to pierce any opposing body ; but 

 besides all these, there is a soft filament (inferior cirrus, fig. 7«) that 

 originates from a bulb near the base, and is long enough to reach 

 considerably beyond the extremity of the foot. This is evidently a 

 feeler, with which the worm acquaints itself with the nature of the 

 opposing body, — whether an enemy that it needs to repulse by the 

 extrusion of its formidable weapons, or a feebler animal that it can 

 overcome and make its prey. To assist its tactic powers, there are 

 besides many tentacular filaments on each side, which originate from 

 the dorsal branch of every alternate foot ; these are smooth and subu- 

 late, and, except in their lesser size, resemble the palpi. The spines 

 (fig. 8) are of a light yellow colour, tapering from a broad base to 

 an obtuse point, smooth and transparent. The bristles (figs. 9-12) 

 are brown, with a bronzed lustre, various in size and strength, but 

 all of them quite smooth. The surface of the belly has a pearly 

 hue, and the skin is thickly covered with minute vesicular granules 

 (fig. 13), similar to those which are seen on certain parts of the foot. 

 The use of these is probably to give the worm a firmer hold on the 

 ground, and prevent any retrograde movement fi-om the various evo- 

 lutions of the feet. In examining this complicated structure, it is 

 scarcely possible to refrain from some expression of surprise. " In 

 figuris animantium (etiam minutarum) quam solers subtilisque de- 

 scriptio partium, quamque admirabilis fabrica membrorum ! Omnia, 

 enim, quae quidem intus inclusa sunt, ita nata atque ita locata sunt, 

 ut nihil eorum supervacaneum sit, nihil ad vitam detinendam non 

 necessarium*." 



From the remarks of Audouin and Milne-Edwards, it appears that 

 Aphrodita hystrix is subject to considerable variety in size, shape, 

 and in the length of its feetf ; and of course it would be frivolous to 

 found any distinction of species on these particulars. But an inspec- 

 tion of their figure shows Aph. hystrix to be a more hispid worm 

 than the one now described ; and there are other characters which 

 seem to me sufficient to prove them distinct. 



Obs. I have seen only two specimens ; — in one the scales were 

 exposed to the naked eye, in the other they were hidden by an 

 earthy-coloured felt. The species is evidently more nearly related to 

 Aph. aculeata than to Aph. hystrix. I have compared specimens 

 nearly of equal size, and the absence of the coloured bristles in Aph. 

 borealis at once draws attention to it. It is besides much less 

 hairy over the feet, and there are no brown spines inclined backwards 

 and upwards on the back. 



(a) Berwick Bay, Dr. Johnston. 



* Cicero de Nat. Deor. lib. 2. 



t Hist. Nat. du Litt. de la France, ii. 74. 



