384 



ORGANS OF DIGESTION. 



(124. g.} open by a 

 short common ductus 

 choledochus into the 

 duodenum, beside the 

 large common opening 

 (124. i.) of all the con- 

 stituent follicles of 

 this great reniform 

 pancreas (124. h.) The 

 long narrow small 

 intestine (124. i. k.} 

 forms seven convo- 

 lutions on the right 

 side and presents a 

 distinct valvula coli 

 (124. L) where it ter- 

 minates in the short 

 straight colon (124. /. 

 m.) wider than the rest 

 of the intestine. 



The pancreas presents every stage of the development of 

 this important gland, as permanent adult forms in the class of 

 fishes, consisting in some of mere folds of the duodenum 

 of one simple tubulus in the ammodites tobianus, in others as 

 the lophius, cJi&todon longimanus, fistularia, and pleuronectes 

 presenting only two simple follicles or appendicula ccecapy- 

 lorica, three in the perch, four in the bream, five in the 

 chcetodon zebra, some dozens in the clupea (123. A. d. d.) the 

 gadus (123. B. i.) and most of the osseous fishes, and four or 

 five hundreds in the scomber Mediterraneus where they 

 open by six short ducts ; these pancreatic follicles constitute 

 a large reniform mass surrounded with a strong muscular 

 tunic in the xiphas (124. h.) among the osseous fishes, and in 

 the sturgeon among the chondropterygii ; and in most of 

 the cartilaginous plagiostome fishes they form a compact 

 conglomerate gland, the component tubuli of which are nearly 

 as fine as those of the liver and aggregated together into 

 lobules and lobes. In some fishes, as the centriscus, no trace 

 of this organ is perceptible. The large pancreatic follicles 

 or appendicula pylorica of fishes, so variable in number 



