XII LIST OF ILLUSTRATIONS. 



Drymwn.^ herrern^ 119 



DryiiKnis herrenv veracruzeiisis 1 20 



Otohhne hemisticta 132 



Skull of Morosaurus acjilit^, posterior view. Proatlas; lateral plate of atlas; 

 odontoid process or centrum of same; exoccipital; intercentrum of atlas; 



neural canal; parietal; postorbital; squamosal; supraoccipital 152 



Mommunis agllk. Front view of right fore foot; carpal bone; nietacarjjals; 



front view of the right hind foot; digits loo 



Oblique posterior view of the skull of Morosaunta affllis. Exoccipitals; fron- 

 tals; foramen magnum; occipital condyle; parietals; post frontals; supra- 

 occipital ; squamosal 1 55 



Right half of the pro-atlas of 3[oros(turus agilis. Lateral view; anterior end of 



same 1 5S 



Anterior view of atlas of Morosaurus agilis. Intercentrum of atlas; neural 



arch ; odontoid ; rib facets 1 59 



Side view of axis and part of atlas of ^foro■<iaurus grandis. Left half of neural 

 arch of atlas; possible intercentrum of axis; oilontoid })rocess; posterior 



zygapophysis KiO 



Ventral view of axis of Mornsanrus agilis. Intercentrum of axis; jiosterior 



zygapophyses; transverse processes IHl 



Ventral view of atlas and axis of Camptosauriis. iVtlas intercentrum; axis; 



axis intercentrum ; facets for ribs 1 (U 



Ischia of Morosaurus, interior view. Distal ends; face for ilium; distal 



extremity ; face for pubis ; symphysis 1 64 



Vitrinella oldroi/di. Top view ; side vie w ; basal view 167 



Vitrinella eshnauri. Top view; side view ; basal view 1 6.S 



Vitrinella alaskensis. Top view; side view; basal view 169 



Vitrinella (Docomphala) stearnsi. Top view; basal view; side view 170 



Vitrinella { Docomphala) berryi. Top view; side view; basal view 170 



Cydostrema xantusi. Top view; side view; basal view 171 



Cydostrema diegensis. Top view ; basal view ; side view 172 



Circulus cosmius. Top view ; side view ; basal view , 173 



Circtdus cerrosensis. Top view ; side view ; basal view 1 74 



Cydostremella calif ornica. Top view ; basal view ; side view 1 75 



Scissilabra dalli. Top view ; side view ; basal view 176 



Macro mphalina occidentalis. Side view ; basal view 233 



Xystcema erythrourum 247 



Gerreomorpha japonica 248 



Benssdaeria mainens'.s, mold of interior of pedicle valve. Natural size 268 



Rensselaeria mainensis, mold of interior brachial valve. Natural size 268 



Skeleton of Gasterosteus vnlliamsoni leptosomus. (Type) 272 



Nearly complete skeleton of Gasterosteus williamsoni leptosomus 272 



Posterior portions of skeleton of Gasterosteus ivilliamsoni leptosomus 273 



Cahi})trohothrium occidentale. Scolex 276 



Calyptrobothrium occidentale. Free segment; genital cloaca; cirrus; o\ary; ovi- 

 duct; shell gland; testes; uterus; vagina; vas deferens; vitelline gland 277 



Calyptrobothrium minus. Scolex 279 



Calyptrobothrium minus. Free segments in coitu. Cirrus of smaller segment 

 retracted; cirrus of larger segment everted and inserted in vagina of smaller 



segment; uterus filled with fusiform ova 2S0 



Calyptrobothrium minus. Cirrus everted; distal end of same, more highly mag- 

 nified ; spermatoza are seen issuing from apex 281 



Calyptrobotlirium minus. ( )va L'82 



