ROSEN, STUDIES ON THE PLECTOGNATHS. 23 



the ventral body Avall. Above the stomach is seen the circular section 

 through the commuuication betAveen the right and left part of the air- 

 bladder. 



Fig. 2. — Diodon lujstrix L. Air-sac (ai)^ which represeuts the 

 enlarged stomach, and ventral body wall (viv), united by chords of 

 connective tissue. 



Fig. 3. — Balistes vetula L. oe oesophagus; st stomach; du 

 duodenum. 



Fig 4. — Spheroides testudineus L. Transverse section through 

 the duodenum. Haematoxylin-eosin. 



Tryckt den 23 mars 1912. 



Uppsala 1912. Almqvist & Wiksells Boktryckeri-A.-B. 



