century mark. On the other hand, the lives of in- 

 sects are sometimes singularly short, although the 

 lives of certain ants are supposed to extend to the 

 length of fifteen years. Queen bees can live for 

 four, and possibly five, years, but the worker bee 

 seldom extends its busy life beyond the seventh 

 week. For these disparities, there is no explanation 

 whatever. 



Now the most striking of the structural features 

 of my hippo campid, is its coat of mail; a hard 

 tough transparent enamel-like skin covering the 

 entire body. The armor is marked off into distinct 

 plates, or shields, each buttressed and interlocking 

 with a rib-like thickening against its neighbor. 

 The nature of this armor tells me at once that the 

 sea-horse is a ganoid, a primitive type of fish, de- 

 scended almost in a direct line from ancestors 

 which roamed the seas long before fishes with true 

 scales were evolved. The sturgeon, both the fresh- 

 and the salt-water form, is also such a fish. 



In the case of the sturgeon and certain of its 

 allies, some fairly trustworthy data are available 

 regarding their longevity. And allowing for prob- 

 able error or even exaggeration, these creatures 

 and their kind are known certainly to live beyond 



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