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Part III. — Twenty-fourth Annual Report 



exhausted by his onerous task and prolonged fast. That this was not 

 entirely due to these causes was shown when the supply of water to the 

 tank was increased, and when it was directed to his corner. After a 

 refreshment of this kind he moved round about with vigour, energetically 

 spouting water on the eggs and fanning them with his fins. 



Towards the end of the month he took a mussel occasionally and 

 swallowed it. This was first noticed on the 26th, and on some days he 

 ate as many as five ; any excess he carried off and ejected, as before ; and 

 at the beginning of May he was as alert, active, and pugnacious as ever. 



On one day at this time I dropped on the top of the egg-mass a little 

 common swimming-crab, about 1| inches in breadth, which, apprehend- 

 ing danger, clung tightly in one of the snout-depressions on the surface 

 of the eggs. It was amusing to watch the lumpsucker ineffectually trying 

 to rout him from the hollow in which he had taken refuge, the blunt 

 snout of the fish preventing a hold being got on the crab. He tried again 

 and again to dislodge or seize the crab. At last the crab turned partly 

 on its side, and extended its widely-opened chelae as if to defend itself, 

 which gave the fish its opportunity. It seized the crab in its mouth and 

 swam off with it to the furthest corner of the tank, where it dropped it. 



Early in the experiment the outer fire-clay pipe was removed and an 

 apparatus fitted up to the overflow, so that all the water leaving the tank 

 passed through two boxes with fine silk-gauze bottoms. This was to 

 retain the larval lumpsuckers when they issued from the eggs. The 

 first of these was got on 5th May, 43 days after the eggs were deposited 

 and fertilized. The daily temperature of the water during this period 

 may be seen by reference to the tables on pages 113 and 284. When 

 the eggs were spawned it was 42'5°F; in April it varied from 41*5° 

 to 46° ; and at the end of the month was 43 7 °F. and 45°F., rising to 

 44-6° and 47°F. in the first week of May. 



For the first few days after the 5th, the tadpole-like larval lumpsuckers 

 were found in small numbers in the overflow-filter every morning, and 

 they slowly increased in numbers. They were very active, swimming 

 with great rapidity by a lashing movement of the tail, a large yolk 

 containing an oil globule at the right side being conspicuous. 



At this time, as I have mentioned, the male parent was most assiduous 

 ill his attention to the egg-masses, redoubling his activities both in fanning 

 and " blowing" upon the eggs. He ate mussels sparingly, sometimes 

 fasting for a few days, and carrying off and ejecting the proffered food. 

 He also continued to chase the other male and drive off intruders. 



Up to the 22ud May, or almost exactly two months from the time the 

 eggs had been spawned, and seventeeen days after they had begun to 

 hatch, the conditions described continued. The young lumpsuckers were 

 appearing in greater numbers, but still not in such abundance as one 

 might have expected. The largest number was about two or three 

 hundred in a day. They were also to be seen adhering to the glass front 

 of the tank, and numbers were thus accounted for. None were observed 

 on the back of the male, a habit sometimes attributed to them. 



It was now noticed, however, that many of the larval lumpsuckers were 

 dead and white, and these were also seen floating in the water. On 

 examination, it was found that the condition of the tank was unsatisfac- 

 tory ; it was obviously rather dirty fiom an accumulation of weed and 

 refuse, and had probably too many occupants for the experiment, and 

 when the egg-masses were examined their lower parts were found to be 

 black and fetid, a circumstance that explained the presence of the dead 

 and whitened young lumpsuckers. Clearly the aeration had not been 

 sufficient for the interior of the egg-masses, The supply of water to the 



