1896.] MICROSCOPICAL JOURNAL. 417 



abdomen as in the higher vertebrates. Draw a view of 

 this section of the smelt. 



9. Thr Alimentary Viscera. — Cut away the side 

 wall of the body cavity so as to disj)lMy the contained 

 viscera, pin the specimen down under water, which must 

 be frecpiently renewed to keep it clear, explore the organs 

 with a probe but do not at first tear any of them from 

 their natural attachments, try to determine the shaie, 

 position and connections of each one. Note the per - 

 toneum, the silvery lining of the cavity; the 7nef;entery, a 

 very thin film running between some of the oruans and 

 attaching them to the dorsal wall of the body ciivity. 

 Find an elongate thin-walled organ filled with gas, ii lies 

 just beneath the vertebral column, it is the swim-bladder. 

 Trace it forward and seek there for a connection leading' 

 from the swim-bladder to the throat, pneumatic duct; can 

 you determine whether it is a hollow or closed duct? 

 Find the oesophagus or gullet and follow it back from the 

 throat to the point where it bends and begins to run for- 

 ward. Here it passes into the stomach (which may be 

 small and empty or enlarged and full of partly digested 

 food, and whose size and shape will vary accordingly). 



At the front end of the stomach the intestine arises, it 

 bends back and runs straight to the cloaca, without hav- 

 ing auy siib-divison into small and large intestine. The 

 mesentery can be clearly seen with some of the portal 

 blood-vessels beside the intestine. The compact organ 

 stiaddling the front end of the stomach is theliver. The 

 vessi'ls from the intestine can be traced to it. It lias a 

 duct not readily demonstrated which leads to the intes- 

 tine. There is no distinct pancreas but there are pocket- 

 like enlargements at the beginning of the intestine which 

 are said lo be pancreatic in function. There is in the mes- 

 entery dorsal 10 the stomach a disiiiict compact rounded 

 organ which is su[)posed to be a spleen. Salivary glands 

 are not present. The large white or yellow organs addi- 



