CHAO: DIGESTIVE SYSTEM OF CUNNER 



Figure 15. — PAS demonstration of 

 goblet cells (go) in the intestinal 

 epithelium (II) of cunner (X 1,000). 

 bm, basement membrane; sb, sub- 

 border; sc, stratum compactum. 



absorptive cells are found always in the infra- 

 nuclear zone. The mucous secreting cells in 

 the intestine (Figures 12, 14, 15) differ mor- 

 phologically from the mucous cells in the pre- 

 esophagus (Figures 3, 4, 6, 9). They are elon- 

 gate with a thin neck extending to the surface 

 and a rodlike root extending straight down to 

 the infranuclear region (Figures 12, 15). The 

 ovoid nucleus of the mucous cell sits at the 

 bottom of this root. Only the mucous secreting 

 cells near the esophageal-intestinal valve of 

 the intestinal bulb are the same shape as the 

 mucous secreting cells of the esophagus. Mucous 



cells also appear to develop in the infranuclear 

 region and grow or extend gradually to the 

 lumen. 



A very distinct type of cell, the rodlet cell, 

 a term introduced by Bullock (1963) for these 

 cells in salmonids, was also found in the mucosa 

 of the cunner (Figure 12). They are distributed 

 throughout the intestine but are more abundant 

 in sections II and III. They are most abundant 

 in the bile duct (Figure 16) and inner epi- 

 thelium of the gallbladder (Figure 17). The 

 elongate, oval, rodlet cells are usually located 

 in the supranuclear region of the mucosa and 





^■'f^^^^'f 



bd 



i-*^-^'- 







Figure 16. — The bile duct (bd) of 

 cunner with abundant rodlet cells 

 (r) (X 400). g. granulocytes; Sm, 

 submucosa. 



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