402 THE MUSSEL CHAP, vir 



2. In the same way slit up the whole intestine, 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 see the direction 

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

 beginning at the last coil. Sketch. 



VIII. I. The gonads appear very similar in both sexes, and fill up a 

 large part of the visceral mass between the coils of the intesthie : their 

 dticts open al the genital apertures (§ II., 6). 



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

 magenta, and examine. 



C. Transverse sections (Fig. 95). 



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

 or spirit into transverse sections about J inch thick, passing obliquely 

 through — 



1. The anterior part of the pericardial cavity, visceral mass, and 

 foot. Note the relations of the mantle-folds, the gonads, the enteric 

 canal (including the rectum with its typhlosole), 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 visceral 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 part of gills, and rectum. 

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



