LIST OF ILLUSTRATIONS. xix 
FIG. PAGE 
90. Fourth Abdominal Segment of Crayfish [5]..........-..... 104 
gl. Crayfish Appendages [5].......0. cece ce eee e ence eeene 105 
92. Longitudinal Section of Crayfish [5]..........e eee eeeeeeee 106 
93. Walking Appendage of Crayfish with Gill Attached [5]...... 107 
94. ThesCommon Crab ioe: sisiaisisiniasiawivisnaie aioe 00 8 6 oud 6 oie wiete nee 108 
95. Early Stages of Shore-crab s+e+ 108 
96. Water-flea [2].......ccceccccce eee e tent teen eee eeeereas 109 
07s Cyclops [2)iisveiwasemseaeesanisiee gees oes cae eee see 109 
98: A Barnacle scsssnwswredsseiuwiese cays essa e ee sewer emer 110 
99: Formsof AmC@b@iccscceri wre coe ses eee oe 22 oes weseuleese 117 
100: Ameeba Feeding [2] .0.0sssa seas secxessiassaciesmennwwars 118 
tor. Amoeba Dividing [2].............. cece ee cee eee eee 119 
to2. One of the Foraminifera........... 06. cece eee ee ener ees 120 
103., The Oniginof Chalk. sig coe. ov ons acd Shae Reames 120 
104. Infasorial, Barthes esos noc ee aie eee Pape SA nectar eee 121 
TOS; UN SUSOMANS icopeteecsuncardnmuaiaranare weer id ta dase see Pao SS Sse wes HE 121 
106. Vorticella [8]....... cece cece ence ee terre nett ne eeenees 122 
107. A Paramecium [5 Joos sve nie neti een e eee einen epee nial niet eiee 123 
108. Structure of a Sponge.... 62... cece eee ee eee eee teen ee eas 124 
109. Sponge Spicules [2]... 60000002 sce cede wenn eee cwes 125 
TIO; “Ghread-cells:. [a]sisa saa wee seugetaus sacs aus eernmaesaeine 130 
tir. Forms of Hydra [8] ......... ee cece cece eee ener e ee eneee 131 
112. Hydractinia [6]... ccc cece sce c sete eee e eect eaten teenees 132 
113. Medusee of Campanularian Hydroid [6]................... 134 
114. The Origin of a Scyphozoan Jelly-fish............-..020005 135 
115. The Structure of a Sea-anemone............ 0.0 eee eee eee 136 
B16. A. Star hish ors weeds egies sys esd Sees eee eee Re E RoR 142 
pry, & Brittle: Starfishiess sa5 0 ¢ esses 230s eee pee enexesas 144 
118. The Structure of a Sea-urchin. 2.0... .. 2. cece eee eee eee ee 146 
E19. A Seaccucumberis « ive cssi 9 sees ees snes coe amen mesmmacs x 146 
120. An Earthwormins ss oss os sa0ss s00 eae Seamer reewas wwe vs 149 
127. A Worm's Stttinssiscs cede as ce vesous repenewstewens wea s 150 
422, Wormncastsi so: s9sigss sacs aacms omen eegamee wea. 150 
123. A Fresh-water Mussel Showing Position of Foot and Siphons.. 157 
124. Fresh-water Mussel with One Valve Removed [5]........... 159 
125. Digestive Tube of Fresh-water Mussel [5]..........-.-.++- 160 
126, Cross-section of Anodon [5].........c cece cece cece eeeeee 161 
127. Nervous System of Anodon [5]............eeeeeeeeeeeeeee 161 
DBs PA SLU ease 8 iar ean oats ens ce Gilet dk ap ay cvdioeear ee alouadncsp bing 52% 163 
DAQY ASSIST pctce sisse Sasso Dacwa.6 aida rasayeicernsns onasbr an n avn buaenacaunsante sites lasses 165 
TBO) AGO Quid [5-06 oases SiziG eussiv nes csayceaes wine asutlermumaamnomm aunt ae 166 
131. Part of a Lingual Ribbon. .......... 0... cece eee eee eee 166 
132. The Circulation of Blood in a Fish...............-.2-.000- 171 
133. Antetnal Organs Of TSH... «...0.synscnemeacaesemaaivics Saks 172 
134. Skeleton Of BiSh. « o.cene seancomeaerdar edie eeanvesetniwiet gous ey 173 
TQ5. VON gue Gl a POG ccc sis sapseasaanp acseansraaySrcimyer a teaca preciagingy sista a sg 182 
136. A Young Tadpole Showing External Gills [2].............. 182 
137. Under Side of Tadpole Showing Coiled Intestine and Internal 
Gills: (2) gota wacarter amg aime matamateicadten: Wee = 183 
138. Heartoof Adult) Frog [2]... sa5 secdsssnaesenmaccraws sexes 183 
139. Blood-cells of a Frog [9]......... cc cee cee c eee e cece eeees 183 
