PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 313 



2. Haddock {Melanogrammus ceglefinis (Linn.), Gill). Eight observa- 

 tions. The rectum showed an average excess of 1.3o over the temper- 

 ature of the water near the bottom, and the circulation an average of 

 5.3°. One fish, after ten minutes spent in a tub of water at 64.2°, 

 showed an increase of temperature in the rectum of 7°. Another, which 

 had been tied by the tail and allowed to swim 15 minutes at the surface 

 (at 69.5°) showed an increase (in the rectum) of 16.8°; still 11.5° below 

 the temperature of the water. On the 6th September, fishing on the 

 "Ledge," the temperature of the water near the bottom at 15 J fathoms 

 was 51.5°, while the recta of the first two or three fishes caught showed 

 as low a temperature as 45°. Those caught later, after fishing in the 

 same place for an hour or more, showed a rectum temperature of 51°. I 

 suppose that the individuals first taken (the tide haviug just turned to 

 flood) came up on the ledge from deeper water, the ledge being of small 

 extent, and showed the low temperature of the water from which they 

 had come, gradually approximating that of the shallower water as they 

 remained longer in it. Theseiirst temperatures are left out of the account 

 in determining the above averages, as untrustworthy, owing to the un- 

 certainty of the temperature of the water by which they had been sur- 

 rounded. Haddock were spawning as early as the first observations 

 (July 30), which fact may account for their somewhat higher tempera- 

 tures than those of cod taken at the same time. 



3. Pollack {PollacMus carbonarius (Lmn.)^ Bonaparte). A single full- 

 grown specimen, weighing about 25 pounds, was taken on the "Ledge" 

 in 15 fathoms. The rectum temi^erature was 2.4° above that of the 

 water near the bottom (42°), and that of the fluid in tlie thorax after 

 opening the heart, 4.5°. Several of the young of this species were taken 

 from the wharves of Prcviocetown at different times and examined. 

 Seven specimens taken from a depth of 8 feet (temperature of water 60°), 

 and measuring about 8 inches in length, showed an excess of 0.5° in the 

 lectum, 0.6° in the stomach (passing the thermometer through the gul- 

 let), and 3.12° by the thermometer in the mass of intestines, &c., next 

 the liver.' They were in company with "tinker mackerel" {Scomber 

 Dekayi, Storer), of a species not observed in this harbor for more than 

 thirty years. 



4. Hake {Phijcis dims (Walb.), Gill). This fish was often taken at 

 the same time with cod and haddock. Specimens were frequently 

 brought up, dead, in the trawl-net. Those taken with a line were often 

 too small for trustworthy experiment, but a very large individual, weigh- 

 ing over 35 pounds, taken August 11, in 25 fathoms of water, at 42°, 

 furnished the most satisfactory observation of the season, owing to the 

 large size of the heart and the sluggishness of the fish, which made it 

 much easier than usual to be sure of the readings. In this instance the 

 difference in temperature of the water near the bottom and that of the 

 rectum was 2.4o, and between the bottom water and the heart, 9.8°. 

 There was an ulcerated patch about 2 inches square on the side of the 



