274 ANACANTHINI. 



for keeping cod alive after arriving in port, by transferring them to cod-chests,* 

 which are kept floating in docks, or other suitable places. Those at Grimsby and 

 Harwich are about seven feet long and two deep, the bottom and sides being 

 made of stout battens placed a short distance asunder in order to admit a constant 

 penetration of water from outside. The top is planked, but possesses an oblong 

 opening and movable cover for introducing or removing the fish. To the ends of 

 each cod-chest ropes or chains are attached in order to easily move it about. 

 About forty good sized cod will live about a fortnight in one of these chests, and 

 about four hundred are constantly in use at Grimsby. For sending to market 

 the cod are removed, killed by blows on the head with a mallet or short club, and 

 then sent to London, where they are known as " live cod," and attain the highest 

 price. Owing to the method employed in killing them they can be crimped some 

 hours subsequently. 



Diseases. — The members of the cod family appear to be very susceptible to 

 disease, especially of the vertebral column, which may become shortened, and has 

 been compared by Dr. Dyce to a form of rickets, occasioning angular or lateral 

 curvature. This may cause a diminution in the extent of surface covered by the 

 dorsal or anal fins, which from this, or other causes, vary greatly in the number 

 of their rays. Sometimes it gives the fish a hunch-backed appearance, or the 

 proportionate length of the head to that of the body becomes far greater 

 than is normally the case. Blindness is not rare among these fishes, especially 

 when in confinement. In the thirteenth volume of the New Sporting Review may 

 be found a most interesting account of a visit to Colonel McDowell's vivarium 

 for codfish in the Mull of Galloway. An excavation was formed in the rock about 

 fifty feet in diameter, and at low tide about eight feet of water remained in this 

 basin, and six feet more at high tide. It was observed as a curious fact that fish 

 when they have remained long in this pond always became blind ; this was 

 supposed to be due to there not being sufficient shelter for them from the heat 

 and glare of the sun owing to the shallowness of the water as compared with the 

 depths of their usual haunts. During the past year when visiting an aquarium 

 in the north, supplied with pure sea- water, I observed several of these fishes blind 

 with one or both eyes : the eyeball in those which were not totally deprived of vision 

 moved on the blind, similarly to that on the sound side. In some examples of the 

 common cod the pupil instead of being circular was transversely oval, or even 

 pear-shaped, probably due to an adhesion of the posterior surface of the iris to the 

 lens or its covering. The pupil was either dull or greenish, while in some a film 

 appeared to cover the eye externally. Without the opportunity of examining 

 these eyes it would be difficult to determine the exact lesion, but I am disposed to 

 think that the theory advanced at Colonel McDowell's was the correct one.f I 

 was lately observing a fine school of bibs which had been upwards of eighteen 

 months in the Westminster Aquarium, where the water had not invariably been 

 particularly clear, nor had all of it come direct from the sea. Among these 

 numerous cases of blindness were not apparent. Before, however, attributing this 

 immunity entirely to the character of the light we have to consider the relative 

 susceptibility of such in the common cod to what obtains in the bib. The cod, 

 although hardly a deep-sea fish, resides in localities at 25 to 100 or more fathoms, 

 while the bib, although it lives in deep waters during the winter, approaches the 

 shore in spring and summer, and consequently does not so invariably remain in dark 

 or semi-dark places as does the cod. The "presence of parasites may not only alter 

 the colours of the fish as shown by its being of an unnaturally light tint, but 

 also by the infected spots turning black as seen in the speckled cod (p. 225). 



Genus, I — Gadtjs, Cuvier. 



Merlangus, Cuvier : Morh.ua, Risso : Pollachius, Nilsson : Melanogrammus and 

 Brachygradus, Gill : Boreogadus, Giinther : JEglefinus and Qadulus, Malm. 



* These have been described by many recent authors, as Buckland, Holdsworth, &c. 

 f Mr. Dunn observes that injuries caused by hooks or blows on the snout may occasion 

 blindness in these fishes. 



