of the Fishery Board for Scotland. 287 



The Growth of the Halibut. 



A specimen of the halibut, which was obtained for me by Mr. Ingram, 

 the Fishery Officer at Aberdeen, may possibly throw some light on the 

 growth of this fish. It was caught at Iceland by hook in the spring, 

 and landed at Aberdeen. It measured 64"0cm. (25 inches) in length, 

 and weighed 2'350 kilogrammes. On the under surface, extending the 

 whole length and breadth of the fish, were certain markings, part of 

 which was plain and part obscure. The following was vei-y clear : — 

 " T. M. 1901," and it was succeeded by what appeared to read "AGLI," 

 but may have been meant to represent "AUGT," or August. The 

 marks were obviously made with a knife, and the curves were angular ; 

 the cicatrix was very narrow and linear and attached to the subcutane- 

 ous tissue, and I suppose it occupied the same relative position in the 

 surface of the fish at first, the skin growing equally all over. 



I am informed by Mr. Ingram that the mate of the vessel which 

 brought in the fish (the Cas2Jania) states that in his time it was a 

 common custom for the fishing apprentices at Grimsby to " engrave " 

 their names in this way on small halibut, and then +^vow them over- 

 board. If the date is authentic, it would show that tiie growth of the 

 halibut in proportion to the size it attains is not rapid, because it implies 

 that about two years and eight months elapsed after the marking was 

 made, and the fish must at the time have been of a certain size. But 

 a plaice of about the length given would be probably more than six or 

 seven years old at least. 



Reversed Action of the Gill-cover in Plaice. 



It may be worth recording that the plaice in the large pond at the 

 Bay of Nigg Laboratory frequently exhibit a reversal of the usual action 

 of the gill-cover under certain conditions. In the process of respiration 

 fishes take in water by the mouth, and by a process like thit of 

 swallowing expel it by the gill-openings. But when the tame plaice in 

 the pond cling to the side at feeding-time, they very commonly push 

 their snout and head for some distance out of the water, and it may 

 then be observed that the water is spouted upwards from their mouth 

 as a little fountain, an inch or so in height. In this case it is evident 

 that the water is drawn in through the gill-openings behind, passes 

 over the gills, and is then expelled by the mouth. The observation has 

 some interest in connection with the known habits of some other fishes. 



EXPLANATION OF PLATE. 



Fig. 1. Leptoeephalus Morrisii, natural size. 



(la.) Head enlarged, side view. 



(16.) ,, ,, dorsal view. 



Fig. 2. Lei^tocephalus pundatus, natural size. 



(2a.) Head enlarged, side view. 



(26.) ,, ,, dorsal view. 



Fig. 3. Fierasfer dentcUufi, larva, natural size. 



(3a. ) Anterior part enlarged. 



