" _dubius_, 32, 33 " _ferrugineus_, 34 " _flavipes_, 35 " _flavo-vittatus_, 37 " _frontalis_, 37 " _graniger_, 32 " _laevis_, 39, 44, Plate xvii. " " description of, 35 " " flagellum of, =35= " _lugubris_, 36 " _maculicornis_, 37 " _melanocephalus_, 33 " _mexicanus_, 35 " _mixtus_, 33 " _montezumae_, 32 " _musculus_, 35 " _nemorensis_, 36 " _nigra_, 32 " _paulensis_, 32 " _pictus_, 34, 44, Plate xiv. " description of, 33 " flagellum of, =33= " _poeyi_, 35 " _pruinosus_, 37 " _quercum_, 36 " _rathkei_, 35, 36, 44, 45 " " description of, 34, Plate xvi. " " flagellum of, =35= " _ratzeburgii_, 44, Plate xviii. " " description of, 36 " " flagellum of, =36= " _scaber_, 28, 44, Plate xiii. " " description of, 32 " _scaber_, development of, 9 " " flagellum of, 32 " " Milne Edwards, 33 " _spinifrons_, 39 " _striatus_, 34 " _sumichtasti_, 35 " _syriacus_, 35 " _tetramoerus_, 34 " _trilineatus_, 34 " _trivittatus_, 34 " _truncatus_, 37 " _urbicus_, 35 _Porcellionides_, Miers, 37 Preservation of Woodlice, methods of, 16 Pro-ectoderm, 10, inset facing =10= Pro-endoderm, 10, inset facing =10= Protoplasm, formative, 10 _pruinosus, Metoponorthus_, description of, 37 pseudotracheae, 31 _pulchellum, Armadillidium_, description of, 42 _pusillus, Trichoniscus_, description of, 22 Purbeck Beds, 2 Quay-louse, 20 Quay lowders, 20 _rathkei, Porcellio_, description of, 34 _ratzeburgii, Porcellio_, description of, 36 Reproductive organs, 8, =8=, =9= _roseus, Trichoniscus_, description of, 24 Roule, Professor Louis, 9 Sandstone, old red, 1 Sars, Professor G. O., 17, 23 _scaber, Porcellio_, description of, 32 Scharff, Dr. R. F., 17, 19, 23, 45 Seminal reservoir, 9, =9= Socchetre, 16 Sow bug, 15 Species, distribution of, 43 St. Anthony's hogs, 16 Stebbing, the Rev. T. R. R., 19, 21, 35, 44, 45 Swanley Horticultural College, 14 Tertiary deposits, 2 Testes, 9, =9= Thorax, 2, 3 Thrush louse, 15 Tiggyhog, 15 Tracheae, 6, 31 Trichoniscidæ, characters of, 18, 22 _Trichoniscoides_, 21, 22, 26 " characters of, 17, 18, 25 " _albidus_, 44, 45 " " description of, 25