Show I HOW ALL CREATION CHEWS CHES w. w r 1 The Horseshoe Crab j. j A. A Animals 1 S TL That 1 nal Have naVe U Has Teeth on Its Legs Teeth in Their Liu Li- Li a 1 u j Stomachs or on Their Legs and How flow They Seize The Sharks Shark's Rows of Vicious T The Elephant Uses Only Two of These an and d G Grind r Z- Z Zd n d Th Their 1 roo Food 1 d Teeth et t Grinders at a Time can be w worn m with Hh propriety the Tha j f F the kinds kind and sizes size of teeth there ere is no OF O end end seemingly The truth of this statement state went ment is indicated by byan an interesting exhibit of teeth r recently installed in the American 1 Museum of Natural History in New York city city- A study of this exhibit not only shows how all creation creation creation crea crea- tion chews but also imparts much information about the structure of teeth their location modo of implantation growth and replacement A bulletin issued by the museum contains contain a S description of the odd varieties of tc teeth th shown in inthe inthe inthe the exhibit from fro the complicated apparatus called lantern worn by the tho sea sea- urchins up to th the fangs of the lion The former fonner consists of five pyramidal jaws each carrying camin along a along along long slender tooth of continuous growth which moves forward in the jaws as it wears away at atthe the point The horseshoe crab wears nears his teeth on his legs at the first joints of which is a series of spines pines and sharp points The food is torn to bits bite on these and worked into the mouth The lobsters lobster's teeth arc are to be found on his fourth to ninth appendages Some of them are adapted to seizing the food others to grinding it The exhibit also reveals the little known fact that that tho the beetle and worm boast boas teeth as useful and efficient effi clent a as any Quoting further from this bulletin There are teeth of many the typical typical cal cli tooth of n a ner vertebrate er cr boned back-boned animal of pulp in a cavity which by deposition of limo lime in m I its S exterior portion becomes dentine ivory or bone forming the body of the tooth enamel overlying the dentine on the crown A 1 The Beavers Beaver's Chisel tk I I t h ise isei i Inc Incisor i t In Man Mar the Teeth AreS AreSe l lin I 1 in Distin Y Separate Sockets and Separated h by bya r a lc 1 Membrane from the he Surrounding Bon Bone Cl of the tooth and n cement usually surrounding the base and md sometimes covering part or all 11 of the enamel of the cro crown n The teeth of some animals animal however tho whale sperm for example have no enamel whatsoever Teeth according to their up make vary in growth Some teeth grow for tor only onh a limited time Others more energetic continue to grow throughout life In the first case the interior cavity CI by the pulp gulp tUla fills up and growth ceases In the tho latter instance tho the pulp cavity ity remains open thu the tooth is continually pushed outward outward out out- ward and layer after r layer of ot dentin forms n at atthe atthe the base The continuous growth h of some teeth is illustrated in this interesting exhibit by a n section section sec sec- tion of an elephants elephant's tusk containing a wrought iron bullet The bullet was fired find into the hollow base of the tho young tusk and the continual formation formation forma forma- tion of dentin resulted in embedding the tho bullet in Solid ivory In uIn man as in most lo 15 the teeth are set in distinct separate s sockets socket and are separated separated separated sep sep- b by a membrane from Nm th thi surrounding bone But nature has other wa ways s 's of GI implanting teeth The extinct sea reptile known to the scientist ad aci as ichthyosaurus had bad his teeth planted in a continuous shallow groove as was the habit with certain birds which lived many centuries ago Modern birds however have adopted the fashion of going toothless Another sort of attachment of the teeth is by means of a bony union of the outer side of the teeth with the inner side of the jaw In a fourth LSD case the tha base of the tooth ia is 3 The Powerful Jaws i L i of the Lion I CI J J I completely fused fazed with the side of ot the Jaw It h is another evidence e of a n beneficent nature turc that man the only creature who is g given gen en to having his hb hist t teeth h extracted does not have his teeth implanted In fn this thi last sst way Some animals have e the tho advantage ad vantage of tenth which arc c more or less lees movable due to the tho fact that th they y are attached to the by ligaments This Thle is the case with many fishes and sumo some Jm reptiles With snakes th this thu arrange arrangement e. e ment went facilitates the swallowing of the food The bulletin next describes the t teeth eth of those animals that have luwe only ono set which nature de de- to lost last through a lifetime Most mammals like roan man have hav two eats a sets a temporary and a 11 permanent per per- manent nt No mammal ha has more than two Generally Gen Gen- a orally a tooth is replaced by another forming below it As the new tooth grows the roots root of ot the old on one are absorbed until finally it falls i out Most lost reptiles and fishes however h hn naw as' as several series cries of teeth EO so that more or orless orless or orIus less Ius continuous loss 1035 and replacement are provided provided pro pro- vided for The shark has lias several rows of teeth one behind the other and as fast as the t teeth tb in th the outer row ro aro lost they are replaced by those lhasa in the rear Replacement may maj also be accomplished by th the formation of a new t tooth oth beside the old one oce which is absorbed at the point of or contact until the developing tooth enters enten- enters the base and replaces it That is the case with crocodiles and lizard lizards The teeth o of the elephant are aro developed at toe the back of the jaw and the entire row moves mo slowly forward the front part of ot each tooth coming coining into use first an and wearing rearing away While six teeth are developed eloped on each side of either cither ja jaw not more than parts of two teeth are in use at any anyone onetime one ona t time Not all animals wear their teeth in their mouths the bulletin continues Some are partial to the location of ot their teeth on their legs while whilo others consider the stomach the ideal situa situa- tion And even among those animals ls who consider consider con con- sider that the tooth's sphere is is the mouth thero are aro differences o of opinion as to just where teeth f grows prows teeth only on hi his upper j jaw w. w n hs animal known as aa Hoffmans Hoffman's sloth eloth haa has tom tetti I I only on the hinder parts of both jaws The gazelles gazelle's tooth are permitted to grow grog on oi both jaws with th the exception of th the front of the upper jaw Despite these and similes eccentricities however most animals anima including the majority of ot mammals have their teeth gm g continuously on the edges of both jaws t Of Of course the form and arrangement of t t teeth of some Kome animals differ to meet the tho various various' circumstances The teeth or saw of the u aw II fish fiEh far rem removed ved from the mouth month are atc desi gd 1 for wounding or kU killing the tho prey pray The tee teeth af at the python are made for seizing and grU gran and are arc long and so as u to hold the PIt prey while the gullet ia Is worked over it The Goth th of cf the ray which feeds on shell fish are adapted to crushing The lions lion's teeth are shaped for cut cot ting ting- rending and killing His posterior teeth am amas It as scissors The Tho elephant grinds his food b be tween teeth whose roughened surfaces act Ilk Hk mill The teeth of ot the tho beaver are Ina sharp and shaped chisel shaped requisite requisite tools tooL for fat oU his lifes life's work of gnawing The fangs tang or front froat teeth of the poisonous snake are really which serve as hypodermic syringes to inject tin poison An opening at the base bue of the fang eon n with the pO poison on sac Reserve fangs backof bad back of tho ilie ones in use soon coon replace those lost lod so 10 o removing the fangs fang of n a poisonous poisonous' snake renders renders' him only temporarily harmless harmles j |