LIST OF ILLUSTRATIONS. 



Dipylidiura sexcoronatum. Head 65 



Dipylidium sexcoronatum. Head 65 



Dipylidium sexcoronatum. Rostellum 66 



Dipylidium sexcoronatum. Mature segment 67 



Dipylidium chyzeri. Head 68 



Dipylidium chyzeri. Rostellum 68 



Dipylidium chyzeri. Mature segment. .- 68 



Dipylidium trinchesei. Anterior extremity of strobila 69 



Dipylidium trinchesei. Hooks, a. Hook from first or most anterior row; h, sec- 

 ond row; c, from third row; d, from fourth row 70 



Dipylidium trinchesei. Mature segment 70 



Dipylidium trinchesei. Gravid segment 71 



Dipylidium pasqualei. Anterior portion of strobila 71 



Dipylidium pdsqualei. Mature segment 71 



Dipylidium pasqualei. Gravid segment 72 



Dipylidium caninum.. Head 73 



Dipylidium caninum. Hooks 74 



Dipylidium caninum. Mature segment 74 



Dipylidium caninum. Gravid segment 75 



Longitudinal section of skull, showing brain cavity of Triceratops 103 



Longitudinal section of brain case of Triceratops serratus 105 



Superior view of brain case of Triceratops serratus 106 



Skull of Brachyceratops montanensis 107 



Longitudinal section of skull of Diplodocus longus 109 



Longitudinal section of skull of Triceratops flabellatus 110 



Liodontomertis perplexus. Antenna from two paratype females, illustrating 



variation in the funicle joints 124 



Pseuderimerus mayeliohe. Antenna of paratype female 125 



Syngenodrilus lamuensis. Seta b of somite 7. cm, circular muscular layer; 



im, intermuscular layer; Im, longitudinal muscular layer 147 



Syngenodrilus lamuensis. Anterior end from which piece was removed for sec- 

 tioning, g, Gizzard; n c, nerve cord; 7/8, septum between 7 and 8 148 



Syngenodrilus lamuensis. Longitudinal section reconstructed from several sec- 

 tions passing through the oviducal pore and the prostate glands, h, Heart; 

 od. p, oviducal pore; oy, ovary; p, prostate gland; st, section; through sac- 

 cular part of spermatheca; s v, sperm vesicle; sy, spermary; 8, 9, etc., num- 

 bers of somites 149 



Syngenodrilus lamuensis. Section through sperm vescicles near lateral walls. 



h, Heart; n, nephridium; s d, sperm duct; s v, sperm vesicles 150 



Syngenodrilus lamuensis. Longitudinal section reconstructed from several sec- 

 tions passing through the spermiducal funnel and related sperm sacs of somite. 

 s c, Sperm cells; sdf, spermiducal funnel; s s, small sperm sacs; s v, sperm 



vesicle 151 



Syngenodrilus lamuensis. Longitudinal section through the dorsal sperm sac 



and the ovisac of one side, d s s, Dorsal sperm sac; o, ova; os, ovisac 151 



Syngenodrilus lamuensis. Wax model of prostate gland reconstructed from 

 sections, posterior view, p p, Narrowed part extending to surface of body 



at prostate pore 152 



Syngenodrilus lamuensis. Semidiagrammatic longitudinal section through 

 spermathecal duct and investing septum, st d, Spermathecal duct; st p, 



spermathecal pore 152 



Diagram showing suggested relations of Syngenodrilus and related groups 155 



