ZOOLOGICAL EXERCISES. 
side of the heart lie the branchiz. On either side 
of the stomach the reproductive organs will be 
seen if they are well developed; they are either 
white, or dark rich brown, or yellow brown. At the 
anterior edge of the carapace observe the cerebral 
ganglion. With a curved needle turn back gently 
the reproductive organs ; below them will be seen the 
liver. It consists of a number of tubuli of a white 
or yellow colour, lying outside and below the repro- 
ductive organs. Sometimes the reproductive organs 
are not well developed, in which case the liver can 
be seen without disturbing them. 
5. Open the pericardium and examine the heart. There 
are three anterior arteries, two inferior, and one 
posterior. Trace them as far as you can. Cut out 
the heart and examine with the microscope; it is 
coated with unstriped muscular fibres. 
6. Alimentary system.—Remove, ‘bit by bit, the greater 
part of the liver. Examine a portion with the 
microscope. The walls of the tubes are formed by 
numerous cells, between which are numerous fat 
globules. Trace back the intestine into the abdomen. 
Notice the whitish slender tubes entering it—cecal 
appendages. | 
7. Cut through the gullet, and remove the stomach and 
intestine, and place it ina saucer of water. Notice 
the two hepatic ducts opening just behind the 
pylorus. Cut open the stomach. It consists of two 
portions, the larger cardiac (anterior), and the smaller 
pyloric (posterior). The interior contains numerous 
bristles in the anterior portion. In the posterior 
part of the cardiac portion are three solid calcareous 
pieces; a short transverse piece, from each end of 
