244 LECTURE IX. 



remarkably long and slender in ScicBua, Upeneus, Lates nobilis, and 

 in the Bonito, tlie Tunny, and otlier Scombridce. The bile is some- 

 times conveyed directly into the gall-bladder by hepato-cystic ducts, 

 and thence by a cystic duct into the duodenum (Wolf-fish, Erythrinus, 

 Lepidosiren) : or it is conveyed by a single hepatic duct, formed by the 

 union of several branches from the liver (^Zygcena, where the duct is 

 very long) : or by two hepatic ducts opening separately into the 

 intestine, as in Pristis: or an hepatic duct from the left lobe joins 

 a cystic duct from the bladder, receiving the gall from the right 

 lobe, and the secretion is conveyed by a ' ductus communis choledo- 

 chus ' into the duodenum, as in Pimelodus : or the bile is conveyed 

 to the duodenum partly by a cystic duct and partly by a distinct 

 hepatic duct, as in the Salmon, in wliich the latter dilates before it 

 terminates. In the Lophius three hepatic ducts join the very long 

 cystic, which duct sometimes .dilates where it receives them. In the 

 Turbot I found numerous hepatic ducts, some of which communicated 

 with different parts of the cystic duct, and four opened into the 

 dilated termination of the ductus communis. (Prep. 811. A.) In the 

 Galeus the cystic duct runs some way through the substance of the 

 liver, and sometimes between the tunics of the pyloric canal of the 

 stomach, before it enters the commencement of the wide intestine, 

 near the beginning of the spiral valve. The gall-duct in the Sturgeon 

 and Planirostra {fig. 61.) terminates at a greater distance above the 

 valvular intestine. The ordinary position of the entry of the bile 

 into the alimentary canal in Osseous Fishes is at the commencement 

 of the small intestine near the pylorus. The terminal orifice of the 

 gall-duct is often supported on a papilla, as in the Sturgeon, the Skate, 

 and the Labrax lupus. In the Bream I found the short cystic duct 

 opening into the fore-part of the cardiac portion of the stomach. 



In most Osseous Fishes the intestine buds out at its commencement 

 into long and slender pouches, or cteca, into which it appears 

 that the food never enters, and which, therefore, increase the direct 

 secreting surface of the alimentary tract, over and above the extent 

 of the mechanism for pounding and propelling the chyme, or of the 

 vascular surface which selects and absorbs the chyle. By a very 

 gradual series of changes of these CfEcal processes, within the limits 

 of the class of Fishes, we are led to recognise them as liomologous 

 with the conglomerate gland called ' pancreas ' in Man, The secre- 

 tion of the rudimental representatives of this gland is so like the 

 fluid which the ordinary mucous surface of the intestine eliminates 

 and sets free from its capillary system, that conditions of the ordi- 

 nary alimentary tract exist in some fishes which render needless the 

 development of the special accessory surfoces. The Dermopteri show 

 no trace of pancreas : their whole digestive canal is simple ; the whole 



