IV 



Page 



B. Propagation 51 



a. The sexual propagation 51 



b. The non sexual propagation 51 



3. Faculty of regeneration and tenacity of life 52 



VI. History of development; 



{Ontogeny) 54 



1. Progressive development 54 



a. Early stage of the Brisiuga 55 



b. Development of the disc 57 



c. Development of the arms 58 



d. Development of the ambulacral skeleton 60 



e. Development of the cuticular skeleton 63 



f. Develoj)ment of the spines 63 



g. Development of the pedicellaries 64 



2. divergent development 66 



a. Individual variations 66 



b. Accidental variations (monstrosities) 68 



VII. Distribution and occurrence: 



{Chorology) 70 



a. Horizontal distribution 70 



b. Vertical distribution 71 



c. External conditions of existence; special occurrence 71 



YIII. Remarics on Homology and Affinity: 



{Fhilosophy) 73 



A. General Homology: 



1. On the scientific significance of the genus Brisinga, considered from the 

 stand-point of the Darwinian theory 73 



2. On the fundamental form of Echinoderms and of their morphological indi- 

 viduality, as illustrated in the genus Brisinga 75 



3. On the phylogenetic relationship of the Echinoderms to other animal types 78 



4. On the genealogical relation of the several groups of Echinoderms to each other 81 



B. Special Homology: 



5. On the relation of the genus Brisinga to the Asteroidea in general ... 85 



a. Homology of the ambulacral skeleton 8 / 



b. Homology of the skeleton of the skin 90 



c. Homology of the spines "0 



d. Homology of the pedicellaries 91 



e. Homology of the interior organs 91 



6. Relation of the genus Brisinga to now living star-fishes 92 



7. Relation of the genus Brisiuga to extinct star-fishes 93 



8. Comparison of the 2 species of Brisinga 94 



9. On the systematic position of the genus Brisinga, with remarks on the 

 classification of star-fishes in general 98 



10. Diagnoses of Family, Genus and Species 101 



Explanation of the plates 103 



