290 TIME. 



they breed very fast, their increase is sufficient to meet 

 the demands of their superiors in organization. At 

 least, I find that my well-filled Tanks need no other 

 supply than this, and what the more predatory kinds 

 occasionally obtain by the death of their fellows. For 

 amusement, indeed, the Actinise, the Madrepores, the 

 Prawns, and the Crabs, may be fed; and then the 

 best diet is the lean of raw meat, cut into minute frag- 

 ments ; but it should be very sparingly done, and the 

 rejected atoms carefully removed, lest putrefaction set 

 in and spoil the whole. 



INSTRUCTIONS FOR COLLECTING. 



Time. — What is commonly called loiv-ivafer — that 

 is, the time when the ebbing-tide recedes to the utmost 

 point — is the period to be chosen for shore-collecting, 

 as comparatively few marine animals or plants habi- 

 tually live in situations where they are long exposed 

 to the air and sun. But the lower the level, the 

 more rich becomes the harvest ; and hence the time 

 of spring-tide is the most productive, when the recess 

 of the tide is the greatest. Spring-tides occur twice 

 every month, viz. about the time of new and full 

 moon ; the very best tides of all are those of the 

 second day after the change of the moon ; but for 

 two days before and two days after that, they recede 

 very far ; so that we may consider those weeks which 

 commence two days before the change of the moon 

 and end five days after it, as good collecting periods, 

 while the alternate weeks are nearly useless. The 



