THE COMMON MUSSELS. 43- 



gullet {guT) is seen to have longitudinal ridges, and above it is the 

 supra-sesophageal cavity. Between the two labial palps (o Ip and 

 Up) on each side are the gills {gill), and above their point of attach- 

 ment the anterior retractors {a rt) . The foot {ft) is represented 

 between the mantle-lobes. 



Fig. 42. This section is through the hind part of the base of the 

 foot. The two anterior retractors {a rt) are still seen, and above 

 them the stomach (stm). Below the stomach is a narrow part of the 

 cardiac caecum. On the left of the stomach to the dorsal side is the 

 forward coil of the recurrent intestine {re int) — note that the right 

 hand of the plate is to the left of the mussel — and near the base of 

 the gills is the returning coil of the intestine {int). The supra- 

 eesophageal cavity ends a little in front of this section. 



Fig. 43. This section is taken just behind the pericardium and 

 in front of the posterior adductor. The posterior retractors (j? rt) 

 form a great part of the section. Above and between them are on 

 the left the pyloric csecum {p c), containing the crystalline style, on 

 the right the recurrent intestine {int), and above them the rectum 

 {red). The space above the base of the gills is very lacunar. 



Fig. 44. This section is taken through the region of the posterior 

 adductor {p ad), which stretches across the section. Above it are 

 the posterior ends of the retractors {prt), and between these the 

 pyloric csecum {p c), with the recurrent intestine {re int) leaving it 

 and joined with it to the right. Above these is the rectum {rect). 

 The cavity above the rectum in this and the preceding figure is 

 enclosed by the joining of the mantle-lobes above the posterior ad- 

 ductor. Below the adductor are seen the two gills of each side. 



