72 Miscellanea Zoologica. 



Hab. Under stones between tide-marks ; abundant in Berwick 

 Bay. 



Description. Body from 3 to 6 and sometimes even9 inches long, 

 tapered a little towards each extremity, rather less than a quill in ca- 

 libre, the ventral surface flattened and furrowed down the centre, of 

 a dirty brown or yellowish colour much stained from the internal vis- 

 cera : head somewhat flattened, biannular, small, naked, marked on 

 each side with a curved black line, the two segments posterior to it 

 without filaments or feet : segments numerous, rather narrow ; from 

 the anterior margin of the fourth, which becomes suddenly larger, 

 arises on each side, but dorsad, a bundle of filaments shorter, gene- 

 rally more tortuous and of a paler colour than the others, which arise 

 from the sides of the following rings down about one-fifth of the 

 length of the animal, and a few remote filaments are dispersed irre- 

 gularly on the rest of the body : there are two rows of slightly pro- 

 tuberant small papillary feet on each side, with a considerable inter- 

 val between the rows, each papilla armed with from 3 to 6 bristles, 

 the bristles of the superior longer, slenderer and more acutely pointed 

 than those of the inferior, which are few in number, stout and curved 

 near the apex : no spines : anus terminal, forming a plain aperture 

 with a dorsad aspect. 



C. Medusa lurks under stones, in a somewhat muddy soil, in 

 which it forms burrows similar to those of the earth-worm, and into 

 which it retires slowly when disturbed. The filaments by which it 

 is so remarkably distinguished, and which curl around it like as 

 many parasitical worms, are the branchiae, or organs through the 

 medium of which the blood is exposed to the influence of the air, 

 and fitted for the purposes of life. They take their rise from above 

 the dorsal feet, some from the back itself, are about 20 in number 

 on each side, tortuous or extended, unequal in their lengths, the 

 shortest being placed anteriorly, but the gradation is not regular ; 

 and they are very easily removed by handling or by immersion in 

 fresh-water. They consist of a large central vessel carrying red 

 blood, surrounded by a white gelatinous transparent membrane, and 

 are consequently of a fine red colour ; but this is liable to variation, 

 for some, particularly the anterior bundles, are often quite white, 

 and others, again, are occasionally spotted, as from a partial stagna- 

 tion of the blood in them. When magnified they appear to be cre- 

 nulated, but are not fringed with cilia. Messrs Audouin and Milne- 

 Edwards propose to restrict the term branchiae to the paler kind 

 which are inserted in fascicles on the margin of one of the anterior 

 segments, and they call the scattered filaments cirri, but surely 



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