Vl 



The animal pole not a fixed point? p. 52 — KUPFFER's view 

 to be preferred to that of HIS, p. 54 — Lateral sense-organs 

 in Annelids, p. 55 ^Metameric arrangement, p. 56r- Inner- 

 vation, p. 56 — Beard versus ElSlG, p. 57 — Lateral ganglia 

 of Annelids homologous to spinal ganglia of Vertebrates? 

 p. 59 — Dermatogenetic part of the cranial ganglia, 

 p. 60. 



Different theories on the metameric structure of the head, 

 p. 61 — Ontogenetic researches, p. 63 — Mesomerism, neuro- 

 merism and branchiomerism, p. 63 — Branchiomerism in- 

 dependent of mesomerism ? p. 64 — No mesomerism at all 

 in the Vertebrate head ? p. 65 — Froriep versus Gegenbaur 

 and Van Wyhe, p. 66 — Mesomerism in bronchial region 

 of Elasmobranchs, p. 67 — Main points on which opinions 

 differ, p. 69 — Unsegmented region of the head, p. 69 — Is 

 there an unsegmented head- mesoblast? p. 70 — Proamnion, p. 

 73. — Diagrams of VAN WYHE and ZlEGLER, p. 74 — Neural 

 crest of head and trunk, p. 76 — Eye muscle nerves, p. 77 



— Auditory vesicle in second segment, p. 78 — Branchiomerism 

 and mesomerism, p 78 — Branchiomerism and mesomerism in 

 lower Chordata, p. 81 — Paired intestinal diverticula among 

 Protostomia, p. 82 — Significance of praemandibular cavity, 

 p 84 — Nature of the trigeminus, p. 87— Oculomotorius p. 88 — 

 Relation of hypophysis and olfactory pits to the mouth, p. 90— 

 Derivation of mouth from gill-slits, p. 91 — Head oj Arthro- 

 pods, p. 94 — Primitive features of the branchial region, 

 p. 94 — The third segment the simplest head segment, p. 96. 



Backward extension of the skull, p. 97 — Ventral occipital 

 nerves, p. P7— FRORlEP's and FuRBRlNGER's views, p. 98 



— Objections against their views, p. 100 — Branchial mus- 

 cles, p. 101 — The origin of the hypobranchial musculature 

 p. 103 — Agreement with the fin muscles, p. 106 — Not 

 all occipital nerves hypoglossus roots, p. 107 — Variation 

 in length of the Selachian skull, p. 108 — Primarily and 

 secondarily epibranchial somites and nerves, p. 110 — FUR- 

 BRlNGER's rule applied to the hypoglossus, p. Ill — Hypo- 

 glossus of Amniotes, p. 113 — Amphibian and Selachian 

 skull, p. 114. 



Head of Amphioxus, p. 118 — First pair of somites, p. 

 119 — Trimerism, p. 121 — Brain vesicle of Amphioxus, 



