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not hold good — soft-skinned creatures should not be conjpared with hard-skinned ; 

 you would not judge of a silk-worm by a hippopotamus, nor a leech by an 

 elephant. Snails have the power of discharging a fluid which eventually hardens 

 into the shell ; thus it is formed, like ours, of continued re-additions from within. 

 If ever a Paludina vivipara should be obtained, as it produces its young alive, 

 and has them during the warm season at every stage, from the fully-developed 

 young one down to the minute gelatinous globule, if a microscope be near, it 

 would be very interesting to put the gummy masses between glasses in order to 

 examine them ; a good glass, indeed a pocket magnifying lens, will be sufficient to 

 show the beautiful structure of the embryo shell, and suggest many useful 

 subjects for study. Whilst speaking of the production of young snails, it will be 

 well now to leave the consideration of popular mistakes, and mention one or two 

 remarkable facts not generally known. Some of them are Moncecious, that is to 

 say, some snails are both male and female in one body ; others again are 

 Dia'cious, as would be expected ; that is, there are males properly so called, and 

 there are females properly so called. A singular thing is said to occur in some 

 water snails, they are born males and become females. Tt will be interesting also 

 to state that some shells are oviparous ; that is, they lay eggs which eventually 

 become of the same species as themselves, some even nurse them as a hen when 

 sitting : whilst others are vivaparous ; that is, they give birth to their young in a 

 living state. It may also be said, that as in Botany certain plants receive their 

 names from odours they discharge, so there are certain snails which obtain their 

 names from smells emitted ; as, for instance, Zonitcs alliarius, the Garlic snail. 

 It may be well to call attention to the beauty of a cabinet of land and fresh-water 

 shells ; the variety of shapes assumeH, the brilliancy of colour as well as 

 transparency, the gradual process of development, and the minuteness of some 

 species, all combine to render them extremely pretty. And if from ordinary 

 observation as the shells lie empty a microscope be used in the examination, so as 

 to view the dissected parts of the creatures (particularly with a good polariscope 

 when the object will bear it), wonders upon wonders are revealed, none being 

 more beautiful than the teeth. Our largest slug, incredible as it may seem, has no 

 less than 28,800 teeth, one row of teeth numbering 180, whilst the trans v|?rse row 

 has 160, which quantities multiplied together give the large number above. 

 The old Roman snail {Helix pomatia) ha.s 21,000. The common water snail, sold 

 in London as the Scavenger Snail, has upwards of 12,000 ; these are all arranged 

 in rows at right angles to each other, but this arrangement is not invariable: the 

 TcstaceUa has a most superb palate fringed with barbed teeth ; remarks will be 

 made about this slug and the Roman snail presently. Some persons may feel 

 anxious to be instructed as to the utensils necessary for collecting shells. My 

 l)lan is very simple : for all water shells, I use an ordinary tin strainer or colander 

 of small size, such as would be purchased for a few pence, and would be used for 

 straining infants' food or pearl barley ; the handle of this is knocked out, and 

 through the hole which will generally be found in it, or a hole purposely made, I 

 fasten a string. This apparatus will very easily go into a coat pocket. I have 

 also a walking stick, the bottom of which just fits the cavity caused by the handle 



