S?o Mr. Osler on burrowing 
spire, and the branchiae removed ; the mantle turned to the 
right side ; the upper part of the thorax cut away to expose 
its cavity, from which the boring trunk and salivary glands 
have been taken. 
a a, The foot; b, the head; c, a kind of platform raised 
above the floor of the thoracic cavity, on which the point of 
the boring trunk rests, and which leads to the mouth ; d, the 
cavity of the thorax ; e, the mantle ; f t the rectum ; g, the 
stomach ; h, the heart, thrown below, and to the right side 
of its natural situation, to allow the opening of the tube to be 
seen ; i, the respiratory trunk ; k, the origins of the muscles 
of the boring trunk ; /, the course of the tube by which the 
foot is supplied with water ; m, its termination. 
Fig. 4. Pholas Candida, one-half larger than nature. The 
fish has been removed, leaving only the adductors, and the 
shell is expanded excessively to show the hinge. 
a> The ligament and process to which it is attached ; 6, the 
lateral process ; c, the posterior, and d, the anterior ad- 
ductor. 
Fig. v. Pholas Candida ; the posterior part of the right 
valve removed to show the lateral muscle arising from the 
point of its process, and passing to its insertion into the side 
of the foot. Its extreme fibres extend beyond the foot on 
each side, and, uniting with the corresponding fibres of the 
opposite muscle, embrace the body. This muscle is so 
blended with the general covering of the body, that it cannot 
be seen, even with a glass, except at its origin ; but its firm- 
ness makes it easy to raise it by dissection, and to display it, 
as in the figure, on a piece of dark paper. 
Fig. vi. Amass of impure calcareous stone, containing a 
