tttt's>fao- Illustrations in British Zoology^twWM, J4&5 



The size of the animal may be conjectured by that of the 

 orifice thus made.K rM ^j .., 



In discarding the old opinion of these animals' employing 

 the agency of a solvent to effect their entrance into substances, 

 we must, nevertheless, admit their power not only to repro- 

 duce and repair their own shells, but: allow them a super- 

 abundant quantity of this secretion necessary for the reparation 

 of all external injuries to this outer covering. The organ 

 which applies this liquid to the different parts of these cases 

 must be supposed to lie in the tubes which are situate in the 

 double-valved neck, as the anterior opening allows the passage 

 of its foot only, without exposing its mouth or gills. If it 

 must be allowed that the secreted fluid has been injected by 

 one or other of the tubes winch pass through the neck, it is 

 reasonable to conceive that this substance, after it is prepared 

 in the stomach, passes through the alimentary canal, and 

 not the abdominal ; and is applied by the animal to the sur- 

 rounding covering when required. When the animal is 

 in its young state, having lull liberty to move around the 

 cavity in every direction, it may be easily conceived how 

 injuries can be repaired; but, when fully grown, and inca- 

 pable of then moving freely, the tube must be supposed to 

 extend itself to all parts of the cavity ; or else the foot or 

 tongue must assist, or be endowed with, this function. 



Guernsey, Jan. 15. l^^mm^ba^^i^^imvgSkm 

 nO- .&sbo ;g9*i ioI bobr/ota binpif sdi 1o 



The student of the interesting subject which this com- 

 munication elucidates, will find additional valuable inform- 

 ation on it in G. J.'s essay " On burrowing and stationary 

 Mollusca," published in our Vol. IV. p. 351— 363, ; where 

 figures of three Saxicavae, a Pholas, &c, are given. — </. Z). 

 ffema anoivaiq b 1o inamsg'fBfna sdi 10 e 5boi & lo nofrBiotaq 

 sdl \d bslosfke -isatrnm^s iUi ni jj ^quh gq c }ffgim t yih&* 

 mooi oiom sb boatietsai Ueo &di ban ^moixnS ba& asbslodSL 



Art. VI. Illustrations in British Zoology. By George John- 

 ston, M.D., Fellow of the Royal College of Surgeons of Edin- 

 burgh."? oi&lz S aDO "{ ^' l ai 19y0 bd'iQVOO Ti t Bn'98d0OlJgfiO 



lliiW 09il8Iinilt 87BV/1& Jon DffB ? 8il9fJ8 ^faVO.plp lO 99nBJ8pJJ8 



Ihis is a minute but singularly beautitul worm, which 

 lives in a small tube composed of gravel and sand, reared by 

 and for itself, amid the entangled roots of corallines. When 

 danger threatens, the worm withdraws entirely into its furrow, 

 twisting its feathery ornaments into a cylindrical shape ; but 

 when all is calm without, the anterior portion of the body is 



D D 3 



