Galba marina. 323 



canal of considerable calibre. Even on strong pressure, the 

 contents do not pass cither by the mouth or anus, except the 

 animal has been dead for some time, but rather escape through 

 the ruptured sides ; an experiment, which seems to prove that 

 there is some valvular apparatus at each extremity. At each 

 sucker there is seen to arise or terminate a large vessel, of the 

 brilliant white of quicksilver, which runs up each side, and com- 

 municates with the blackish firm tube of the branchiae. These 

 vessels are connected -by an anastomosing branch just above the 

 suckers, and by another at the branchiae ; they are tolerably 

 straight, and give oflfin their course small vessels to the sides and 

 under parts. They are evidently filled with air. More deeply 

 seated than these, and lying as it were above the intestine, is ano- 

 ther vessel distinguished by its milk white colour. This vessel is 

 very tortuous and long, and forms a kind of circle, for I cannot 

 determine either its place of origin or termination. It is often 

 bent upon itself, but no branches seem to arise from it ; nor can 

 any communication with the air vessels be traced. It contains a 

 fluid of a thickish consistence, and of a milk white colour. 



This animal inhabits a cylindrical tube, open at both ends, and 

 composed of particles of coarse sand, cemented together by glu- 

 tinous matters.* The tube is so common that it may be found 

 fixed amongst the entangled roots of almost every specimen of 

 Laminaria digitata cast on shore. Many tubes are generally 

 placed together, so as to form an irregular mass, and on breaking 

 through this we expose numerous animals resembling exactly so 

 many maggots in a piece of putrid cheese. The animal crawls 

 with considt'rable quickness over solid and even surfaces ; as 

 might have been conjectured from the structure of its ventral 

 surface, it crawled with ease up the sides of the glass vessel in 

 which it was contained, nor did it hesitate to leave the water, 

 out of which it can live a long time without apparent incon- 

 venience. \Vhcn thrown on the surface of water it seems to have 

 no power of descending to the bottom, or even of locomotion, 



* I \\a.s wont to cou'^ider the tube as the Sabella lumbricalis of Montagu. 

 A similar tube, and ei^uaily common, I know to be inhabited by a very dif- 

 feient animal. 



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