6232 Marine Aquarium. 



for themselves in any ordinary aquarium, though some have particular 

 tastes ; and the carnivorous univalves have to be supplied with appro- 

 priate food, consisting very frequently of their bivalve relatives. The 

 latter are evidently the most troublesome to keep. 



Purpura Lapillus, our commonest muricidal animal, is as easily 

 preserved as procured. It is a hardy mollusk, and will live without 

 food for more than a month. It should be fed with mussels, a small- 

 sized one, an inch or an inch and a half long, being given every week. 

 They seem to form its habitual food. I have kept it with oysters, 

 Modiolas and periwinkles, but it has never molested them. It perfo- 

 rates and devours its victim in two or three days. The perforation is 

 more or less rounded, about TT^h of an inch in diameter, and, as the 

 outer layer of the shell is more rasped away than the inner, somewhat 

 funnel-shaped. The proboscis is inserted through the hole, and 

 attenuated for that puipose ; it varies in thickness accordingly as it 

 is more or less elongated. 1 have seen it inserted. This shell-fish is 

 shy, and not very active in its habits, and becomes more than usually 

 sluggish when kept without food. It will oviposit in confinement, 

 but some capsules deposited in March were not developed in July, 

 when they were unintentionally destroyed. 



I have never fed any of the other Muricidae. Some can be more 

 easily kept than others ; thus, Fusus antiquus is much more active 

 and hardier than Buccinum undatum. 



Natica monilifera belongs to quite a different group of Gasteropoda, 

 the sand-inhabiting mentiferous tribes. It lives well if kept in sand 

 and supplied with food, but cannot endure privation of food. It lives 

 buried, and seldom shows itself It can crawl quickly over the sand, 

 and pursues in it the bivalves, killing and devouring those it can 

 detain in the grasp of its large and flexible foot, which it uses as an 

 organ of prehension. It can kill those the size of a cockle or a little 

 larger, but a full-sized M. solida is too strong for it, and can live with 

 it with impunity. Cockles do very well to feed it with, as they are 

 easily procured, but other bivalves seem to be more to its taste. It 

 always devours its prey buried in the sand. If it captures it on the 

 surface, it buries itself with it. A cockle once a week is sufficient. 

 It will also devour, in aquaria, small M. solida and Mactra stul- 

 torura, Tellina solidula and Donax anatinus. I have tried to feed it 

 with mussels, and observed it exsert its proboscis and touch them ; 

 but it always left them afterwards, without boring. The holes it 

 makes are rather larger than those of the Purpura, but of the same 

 shape and appearance ; they are usually through the umbone. 



