524 MEMOIRS OF THE CARNEGIE MUSEUM 
braOriginvofadistribution wre yesimn, cos tran ae a tore ie seer yee AAT 
Au Cambarusabartoniprobustuswasisecesmis SoCo ee oer kote eee en 449 
GE TSUMIMALy FOL MACtS weeerg sas ee ae Chan mee ees i ned Tee eee 449 
beOrioimmoiidistribubonveere sie eae ene cee ete os oor lite emote ee omneree 449 
Hey Cambarusicarolimuse seta secatstoe cn koa ays ae eine covecoee weiner cae ane camepe eet mS 451 
Ge SUM MAL Yes OL LACUS a ep syee ce ee hese oss cya ene RCo cee omscer ee Relic a Ie eer egos 451 
bvOrioingotadistribution sc seese se eee eee ea ae ee 452 
6seCambarusmmonongalensismmei eemee aero ae iene 453 
GC POuMMAary, (Ol factSin cami sists a sree crews Sie apt recta a are een eros 453 
bss Origin zotadistributionce nc. cers seuss ono oso are eA a eC 454 
(2 Cambarus diogeness aia aihorcrreeioset ois oe CAG eG oun AOR ee meena Oe 457 
GQ OUM Mayle actsyc mest Petals cucesien eis) sire sera Aaa Te re ese eR eae 457 
eOricinvofedistributione ss: aces ay aes race eee ete eons 459 
Se jummanyaofestudvestonudistributioneen ae eee ere eee ae ese orc 462 
Vem errs ETT SMO RAY eresesye vey ape yous auc date) at taped auch -acrrtcbalg pam et Splat ten erearaar ale sure re Ree eg 469 
ie Cara bavustOWSCULUS|s nieratccuns, arsine suchas aero aer reas Merc neR ee oan oie eerie oe 470 
2. Cambarus propinquus and C. propinquus sanborni...............-..-...- 476 
S53 Caml barus li mMOSisicsc. isos co sive: seuss deccuebetercasney aio cdo So ce coer ere Neca eee weno AT7 
Al Cambarus: Gio gemes|scs fe % ico hn yas 35 vies Bs wien a) ARR os outs sree ty ere terete 480 
5. Cambarus bartoni and C. bartoni robustus............-.2+.0..00...--. 486 
6. Cambarus carolinus and monongalensis.............--......+++-++++--:: 489 
AV ANies A CON OMG AW CAUG WEN fara feran cae) cuca 08 So, sulsie nats aa aReee ame aI oo SSA OP ome eet aseee 492 
ipeeopularsknowled seo ficrawtish esac arec hirer re teeter erm on ae 492 
Jpeulthewuselotacrawtlishes asi oodsands bait ae enoee ernie cc eee 493 
3. Crawfishes as scavengers ; their food; their enemies...............-+.... 494 
Awe @rawiisheslasro bnoxious\creaturess-m-pe ereineaeeicr eee eee 496 
VII. BEARING OF THE ABOVE STUDIES ON THE THEORY OF EYOLUTION...........--- 497 
jp uhherVintation—heonyoteDeclViriesseeeee ene cece eer 498 
2. Species, Varieties, and Variations among the Pennsylvania Crawfishes...... 498 
3. Formation of Species by Isolation, as exemplified by Pennsylvania Crawfishes. 504 
PTB TE TOG RA Payor oe rs ts ite Menhees aaa oes iselfere ATS ete a ee eae St ee ene eee 513 
EXP ANATION: O Rick TPAC DES ate, ‘<5 teicnaceits, rncan peaerelste ee oats ein egal ceo Ue TCU Reames 518 
