VI 



TABLE OF CONTENTS. 



Complicated structure of the actinostome. Effects of 

 sections upon living Medusfe. p. 05-li)8. 



Section- 4. Growth of Cyanea. — The young compared 

 to adults of different species. p. 109-112. 



Section o. Histoloytj of Cyanea. — The actinostome and 

 the tentacles, p. 112-114. 



Section 6. Cijaneithe as a famlh/. — Their form ex- 

 hibits a peculiar pattern. p. 114-115. 



Section 7. T/ic ;/enus Cyanea compared with other 

 genera. — Phaccllopliora and Heccfedecomma. Sthe- 

 nonia. Stonoptvclia. Clnysaora. Couthouyia. Me- 

 dora. Patera. Donacostoma. Pelagia. p. 115-119. 



Section 8. The species of Cyanea compared with one 

 another. — Cyanea arctica, fulva, and versicolor. Cya- 

 nea capillata and Lamarckii. Cyanea Postelsii and 

 ferruginea. p. 119 and 120. 



CHAPTER IV. 



THE GENUS PELAGIA AND ALLIED GENERA. 



Section 1. The family of Pelai/idie. — Its characters. 



Nausithoe probably tlic young of Pelagia. p. 121-124. 

 Section 2. The (jenera of Pelagida'. — VsAagxa.. P!a- 



cois. Chrysaora. Dactylometra. Polybostrycha. Me- 



lanaster. Zygonema, p. 124-127. 



Section 3. Description of Pelagia cyanella. — Direct 

 development from the egg; the embryo assumes the 

 form of an ephyra, without ever passing through tlie 

 strobila state characteristic of Aurelia. Comparison 

 of the young with Nausithoe. p. 128-130. 



CHAPTER V. 



THE DISCOPHORiE RHIZOSTOME.E. 



Section 1. The Rhizostomem 



9<^ 



peculiarities. Polystoniy. Constitute a distinct sub- 

 order, with many families, p. 131-137. 

 Section 2. The genus Stomolophus. — Comparison with 

 Rhizostoma. p. 138. 



neral. — Structural | Section 3. The genus Pohjclonia. — Founded upon Me- 

 dusa frondosa Pall., recently observed in Florida. 

 Its peculiar habits; gropes in the mud, and is sel- 

 dom seen floating in the water. Polyclonida; as a 

 family. Generic characters, p. 139-148. 



CHAPTER VI. 



ENUMERATION AND GEOGRAPHICAL DISTRIBUTION OF THE DISCOPHOR^. 



Section 1. Tahular view of the Discophora: known at 

 present. — They form three sub-orders, with fifteen 

 families, p. 149-1 7G. 



Section 2. Geographical distribution of the Discophorcr. 

 — The lower types are the most widely distributed. 

 Distinct Aealephian Faunaa. p. 177-180. 



PAET IV. — HYDROIDiE. 



CHAPTER I. 



CORYNE AND ALLIED MEDUSJE. 



Section 1. General remarks upon the Hrjdroids and 

 naked-eyed Medusae. — Hydra and Medusa form. Bibli- 

 ography, p. 183-185. 



Section 2. The Hydroid form of Coryne mirabilis. — 

 The hydrarium and its structui-e. p. 185-190. 



Section 3. The reproduction of Coryne mirahiliii. — The 

 budding of Ilydroids and Medusa;, p. 190-204. 



Section 4. Histology of Coryne mirabilis. — The adult 

 Hydroid. The Medusa;-buds. The structure of the 

 egg. p. 204-211. 



