°*ri2l? r ] B.\K^h f Tbf Swnffowintj of Stones hy /1tin,*««/t W 



season, they may swallow stones to jJWV^m undue atrophy of the stomach, 

 by functioning as a sum of a 'cllOWfli igunri ditnttg the pc'iod (hi* sc*' fc 

 guarding ihe ha rein. 



(f) Trituration oi food, 



In advancing this tbeoiy, consideration [mist lac given to the structure vt 

 the dijfewive system 01 the various animals wc hi#fl refericd in. 



The food of the pjmepedia Consists mainly of fi«;h squids and cruitacca, 

 their teeth are constructed lor tearuif: And they can neither biv in a clean ci« 

 3i:3fnef nor masticate Small fish are swallowed whole while iarfcer fish arc 

 WrU apatt The oesophagus is long and Urge, allowing eat> passage fur a»iv 

 object which can he taken into the mouth cavity. The stomach is. simple trt 

 form, and auuiuiaiit gastric juice- digests the whole fish. 



In the alligator group, the food consistiii)* of land Of utarine animals, the 

 teeth are used for seizing and (caring | the oesophagus comic cr* w;rli a stomach 

 made ifl> Of two part*, composed of numerous large inu>cular falds a:ai 

 capable of being greatly distended. Theie is »o gi^aid 



The shatka, have sharp vows of teeth lo seize and tear their prey, which 

 constat* mainly of small fitfh, Turn ofi p oniony, or the \shale nsh ii ncl 

 too targe, arc swallowed, there bcniK no mastication, The food readies Ine 

 stomach, composed of Wmgumluial iulds, through a very shui l uesop} atfite, 



Of tie b»ds. wheio tlie food consisls of seeds, fruits, ftva^s, find in some 

 specie*. ?ma1l fcfti and cnistacea. there is an absence cf ;eeth. A beak seitcs 

 the food, ana U is som-cyed by The action of a longne to the oesophagus ami 

 On to 'he iT<in. From the crop it passes, as required, into the gizjurd, where, 

 with the »is>is(nj|Ce of ahfading material, such -is sand, gutvel or ;;mall clones, 

 llie fetid 14 ftt<wr»d In a di^emihtc; lorm- 

 lt will he seen therefore that none oi the animal form* with wlnu 

 gastrotitbs arc associated have a perfect mean? of mastication ot their "tood 

 in the manner m which it i$ Uken 



With the hirds, it is initio apparent thar vtonc-fwallowing' ii a necessity., 

 as they have a true mu.*;Cular gizzard, whereas in the other forms of anim.ih, 

 although it is not a prerequisite to the thorough digestion of their lood- it 

 etoe.-i provide additional assistance iei its triturarioii- 



A study of the digestive sfrucl'tres of the extinct ancestors of the b'rds 

 {if only those parts were jirese rvrd) wnufd do much LO elucidate this 

 apparent phenomenon. 



Conclusion 



In reviewing "The Swallowing ol Stones by Animals", the question is; 

 "Ir. what way will gastroiiths >ie of use to the naturalist Oi scientihc worker;' 



To the £€$logi£ti h P<5 8?cm shown that certain animals have been the 

 means of transporting small quantities of anmes. Ry comparing their appear- 

 ance, polish or unusual occurrence, with or without bone rem.iinK, flfofe is 

 a put-btlnlity IIih( ai least a -rrnutl amount ot tlie Jife in the pasi cmiltl he 

 reconstructed. However* it is highly improbable that paMrohths would ever 

 he important criteria in determining stratigraphy horvfWi. 



For the hioloK'st, there still remain;; much to be observed of the feedivK 

 habits of the animals conc.Tued, as in This way only can accurare decisions 

 he formulated 



T wish to express appretiaiiun and sincere thanks to Mrs. G. Mathaci and 

 Aliss Jill Massetr, of the Geo1»>g> Department Ttbr.iry at the University of 

 Mo I bo time, for their untiring effort? to obtain the many publications requested 

 riurmtf the. preparation oi Ibis paper; to Mr. J. McNally, of (be Kisberiey 

 and Came .Department, Melhoume^ I -effer thanks for the loan of seal 

 ga^trolitlu (FtR- Jj -and the use of •;:npuhli>hed information on the feeding 

 habits of Victorian seals; [ wish to thank Mr. K. D. Gill for arranging the 



