PROTECTIVE MIMICRY. ZZ6 



furnished — and which are often regarded as branchiae — in the 

 form of a funnel ; the sides of this funnel are perfectly closed, 

 and are formed of the filaments of the branchias which lie in 

 the closest contiguity ; the section of the funnel is circular. 

 Each branchial filament has on its inner surface a multitude 

 of fine and minute hairs, which, however, are rendered rigid 

 by having in their interior cartilaginous cells ; these hairs 

 radiate towards the centre of the funnel, so that the space 

 enclosed within the funnel is divided 2:)erpendicularly, by a 

 great number of septa, into a corresponding number of 

 chambers. 



" The new 2Iijxicola of Port Mahon I found, as I have said, 

 among the polyps of Gladocora ; they lived in long mucilagi- 

 nous tubes, which they had formed in the rifts of the coral, 

 and in which they could move about freely. As long as no 

 light was thrown upon them, they protruded themselves just 

 so far as that the top rim of the corona of tentacles was on a 

 level with the tentacles of the polyp, so that when the worm 

 and the polyps were both extended, the coral itself presented a 

 perfectly level surface of cups. Moreover, the fannels of the 

 y[ijxi(:ola were of precisely the same chocolate-brown colour as 

 the polyps ; and when fully extended, the interior of the funnel 

 formed by the tentacles looked exactly like the oral disc of 

 one of the neighbouring polyps, for the radial pinnules were 

 in the same position as those lines which, on the oral disc of 

 the polyp, radiate towards the narrow central oral slit ; in the 

 Myxicola, also, a small central slit was observable, and all the 

 parts which corresponded so exactly in size and position also 

 displayed exactly the same colouring of greenish grey, with 

 radial lines of a lighter hue, and a narrow white streak in 

 the middle. In short, the resemblance, in size, position, and 

 colouring, of every part of the two creatures, was so perfect, 



