402 THE MUSSEL fUAP. vir 



2. In the same way slit up the whole iniesiine, either from the 

 stomach backwards or from the rectum forwards, using the seeker as a 

 guide the whole way, and first examining Fig. 93 to sei^ the direction 

 which the coils take. Note the ventral typhlosolc in the rectum, 

 beginning at the last coil. Sketch. 



\'III. I. 'X\\Q gonads appear very similar In both sexc^, and fill up a 

 large pari of the visceral mass between the coils of the intestine : their 

 duits open at \\\*i. goiilal apciiurcs (§ II., 6). 



2. Tease up a bit of the ovary or spcrmary in salt solution, stain with 

 magunta, and examine. 



C. Transverse sections (Fig. 95). 



With a sharp scalpel or razor cut a' specimen hardened in formaline 

 ur spirit into transverse sections about \ inch thick, passing obliquely 

 through — 



1. The anterior part of the ])ericardial cavity, visceral mass, and 

 fool. Note the relations of the iiiaiitle-folds^ the gonads, the en/eric 

 ainal (including the rectum with its typhlosolc)^ the gills and supra- 

 branchial canals, the anterior aorta and vena cava, and the kidneys 

 and bladders. 



2. The ventricle, auricles, and hinder part of the \ibceral mass. 

 Note the relations of the mantle-folds, enteric canal, gills, suprabranchial 

 canals, vena cava, and kidneys and bladders. 



3. The posterior adductor muscle, hinder jKirt of gill^, and rectum. 

 Ndle the relations of the various parts. Sketch the three sections. 



