66 



Part HI. — Twenty-third Annual Report 



Fullarton adopted the method of keeping the berried females in con- 

 finement, in an open pond, until the eggs hatched ; but in his experi- 

 ments carried out in 1895 the larvae were allowed to escape to the sea as 

 they were hatched. In the present case the young lobsters had to be 

 retained. The arrangement was as follows The berried hens, fourteen 

 in numher, were kept in a wooden tank measuring about 8 feet by 4 feet 

 6 inches by 2 feet deep. The water supply entered at the bottom of 

 the box, and the outflow took place from the surface of the water. The 

 overflow water was led into the hatchery and distributed into the hatching 

 apparatus. As the little lobsters hatched out they were carried down to 

 the hatchery and caught and detained in the hatching boxes. 



In order that a large number comparatively of lobsters be kept in a 

 small area, it is necessary that they each be provided with a hole or pen 

 for shelter. The wooden tank in which the adults were confined 

 was prepared in the following manner. A plank of wood about 7 

 inches wide was hinged by means of large fencing staples to the side 

 of the wooden tank. When horizontal in position it was about 4 

 or 5 inches above the bottom. The space beneath this shelf was 

 divided off by means of bricks set on edge into as many compartments 

 as -were required; in this case seven. The shelf rested on the bricks, 

 and when the tank was filled it was kept down by a suitable weight, 

 some stones or bricks. One shelf was put on each long side. This 

 arrangement permitted of ready examination of the lobsters, as when 

 the superincumbent stones were removed the shelf floated up. revealing 

 the lobsters. They remained there, then, in apparently suitable con- 

 ditions. Each lobster stuck to its pen, its body hid by the shelf, and its 

 projecting antennae alone betraying its presence. Only one lobster died 

 from injuries received through fighting with the other inhabitants of the 

 tank. The large chelae were not tied. 



The young hatched out in batches. The eggs of one female do not all 

 hatch simultaneously, but over a period. In two cases recorded by 

 Herrick, a week elapsed from the time the first larva appeared until all were 

 hatched out. Fullarton found the time necessary for hatching a single brood 

 varied from a week to three weeks, or even longer. The aeration of the 

 eggs attached to the abdominal feet of the female is assured in the 

 following manner. The lobster is seen every now and then with its 

 abdomen stretched out to its full extent and resting on the inturned edge 

 of the telson. The swimmerets are meanwhile gently waved backwards 

 and forwards, in this way aerating the eggs and tending to cleanse them. 

 When the eggs are ready to hatch this facilitates the escape of the larvae. 

 This action was noticed by Coste. The hatching of the lobster eggs at 

 Brodick, Fullarton states, occurred in July, August, and September, with 

 a maximum in August. 



The first young lobsters were observed in the Laboratory, Bay of Nigg, 

 on July 11th; they had then reached the hatching apparatus. They 

 apparently hatch during the night, as each morning there was a fresh 

 addition to the stock. The little lobsters were in the first zoea stage 

 (fig. 66). They were kept in boxes having sieve bottoms, which were 

 placed in the top compartments of a hatching apparatus. They measured 

 about 1 foot by 1 foot by 1 foot, and were painted black. They received 

 light from above only. The number of larvae kept in one box varied, 

 but not more than twenty were knowingly confined together. They were 

 kept in the top compartments in order that they might obtain a share of 

 the food that was being brought in by the water supply, e.g. copepoda, 

 diatoms, and larvae of invertebrates. The water was not filtered. It flowed 

 into the box by a spout and out by the sieve bottom, the arrangement 

 which is followed in hatching the eggs of plaice and cod. 



