426 ANATOMY OF VERTEBRATES. 



however, elongated in the Gymnotus, in which apodal fish, by 

 reason of the peculiar aggregation of the organs of vegetative 

 life in the region of the head, the liver is divided into two short 



o 



and broad lobes connected by a transverse lobule. The liver 

 consists of one lobe in most Salmonoid and Lucioid Fishes, in 

 the Gymnodonts and Lophobranchs, in the Mullets, Loaches, 

 and Bullheads. It is long and simple in the Lamprey and 

 Lepidosiren ; long and bilobed in the Conger. The Lump-fish 

 has a lobulus besides the chief lobe, which is round and flat. 

 There is a short thick convex lobe to the right of the long left 

 lobe in the Lophius. In many Fishes the two lobes are subequal : 

 they are rarely quite distinct, as in the Myxinoids ; but commonly 

 confluent at their base, as in the Wolf-fish, or connected by a 

 short transverse portion, as in most Sharks, the Siluroids, the 

 Polypterus, the Dory, the Coryphene, the Chastodonts, and the 

 Cod tribe. In the Whiting the two chief lobes extend the whole 

 length of the abdomen ; in the Shark about half the length, 

 fig. 352, b (in which the left lobe is cut away). The liver is 

 trilobed in the Corvina, the Clupeoid, and the Cyprinoid Fishes : 

 in many of the latter family it almost conceals the convoluted 

 intestinal canal. The broad and flat liver of the Raiida3 is tri- 

 lobed. The liver is much subdivided in the Sandlaiice and in 

 the Tunny, in which latter fish it presents remarkable modifica- 

 tions of the vascular system. 1 There are few well-established 

 exceptions to the general rule of the presence of a gall-bladder 

 in the class of Fishes. My dissections confirm the statement of 

 its absence in the Lump-fish by Cuvier 2 and Wagner. 3 Cuvier 

 did not detect a gall-bladder in Lates niloticus, Holocentrum Sogho, 

 Sphyrcena Barracuda, Trigla lyra, Trigla cuculus, Corvina dentex, 

 Glyphisodon saxatilis, Lepidopus argenteus, Labrus turdus, Ammo- 

 dytes, and Echineis remora. The gall-bladder is wanting in the 

 Ammocete and Lamprey, but exists in the Myxinoids ; it is absent 

 in Pristis, Zygcena, and Selache, but is present in Galeus, and 

 others of the Shark tribe. The rich series of observations 

 recorded by Cuvier 4 and his able Editors 5 on the gall-bladder 

 and gall-ducts in Fishes have not afforded a clue to the law of 

 the developement of the special receptacle of the biliary secretion 

 in Fishes. The pouch in which the aggregated hepatic ducts 

 terminate in the Selache maxima may compensate for the absence 

 of the gall-bladder in that Shark ; these ducts are enclosed in a 

 broad flat band of dense cellular tissue, fig. 284, /, which passes 



1 cm. 2 xii. t. iv. p. 551. 3 XLVII. 



4 xxin. passim. 5 xii. t. iv. pt. ii. p. 559-569. 



