LIST OF ILLUSTRATIONS. 



Page. 



Fig. la. Upper molars of the brown rat ( Mus) : tubercles in three rows 16 



Fig. Ib. Upper molars of the rice rat (Oryzomys): tubercles in two rows 16 



Fig. 2a. Right hind foot of brown rat, showing long sixth foot pad 17 



Fig. 2b. Right hind foot of house mouse, showing round sixth foot pad 17 



Fig. 3a, fig. 3b. Ears of brown rat and black rat, showing relative size 21 



Fig. 4. Necropsy appearance of normal rat 48 



Fig. 5. Necropsy appearance of plague-infected rat 48 



Fig. 6. Flea, showing the various parts 70 



Fig. 7. Louse Polyplax spinulosus 78 



Fig. 8. Mite Lselaps echidninus 81 



Figs. 9 to 58. Internal parasites of rats and mice 90-109 



Fig. 59. Isolated plague-infected center, Manila, P.I 206 



Fig. 60. Scheme for testing rat-plague infection, Manila, P. 1 206 



Plate I. Mouth parts of Ceratophyllus fasciatus 130 



II. Ceratophyllus fasciatus 136 



III. Loemopsylla cheopis, Rothschild 138 



IV. Ctenopsyllus musculi, Duges 140 



V. Pulex irrilans, Linnaeus 142 



VI. Ctenocephalus canis, Curtis 144 



(7) 



