110 MOLLUSCOUS ANIMALS. 



the ring 1 attached to the point of the dredge, another cord la 

 attached to the middle of the rod, b c, by a knot which em- 

 braces the rod b c, the perpendicular branch A D, and the 

 small cross-bar Df at the point where they unite. When the 

 boat has reached the place of fishing, the dredge is thrown 

 out at the stern in the same manner in which an anchor is 

 thrown out, the last named cord serves to keep the dredge in 

 its place, the plate being turned below till it arrive at the bot- 

 tom of the sea, and to prevent it from being overturned by the 

 way. When the dredge has reached the bottom, it is hauled 

 along by rowing and sailing. Should the dredge be stopped 

 by any rock or irregularity at the bottom, the rope attached to 

 the ring should be pulled. When the bag is supposed to be 

 full, the dredge is drawn on board by the capstan, and the 

 bag is emptied of its contents. 



Different species of sea weed are frequently covered by mi- 

 nute shells, weeds should always be carefully examined. 

 Many of the smaller and microscopic shells are found at high 

 water mark among the fine dross and drifted fragments of 

 shells ; this sand should be brought home and examined at 

 leisure. To facilitate the process, a small wire-cloth sieve 

 should be made, of about six or seven inches square, and all 

 the sand sifted through it, and the shells left. See plate V., 

 fig. 7. 



MOLLUSCOUS ANIMALS. 



Many species of worms, and other soft invertebrate animals, 

 are to be caught also by the dredge. There is no way of pre- 

 serving these animals except by putting them in spirits. Ani- 

 mals of this kind are still very imperfectly known; notwith- 

 standing the researches of Lamarck, Poli, and other celebrated 

 naturalists. Every opportunity should, therefore, be embraced 

 of bringing them home ; indeed, we are still little acquainted 

 with those which inhabit our own seas. Colonel Montagu and 

 Dr Grant have, however, thrown much light on this depart- 

 ment. 



When animals of this kind are procured in foreign parts, a 

 careful noting of the latitude should be taken ; and it should 

 be stated, whether they live singly or are congregated, if they 



