TABLE OF CONTENTS, 



Vll 



Sjection 5. Adult Medusa of Coryne (Sarsla) mirabilis. 

 — Its form varying extensively, its habits and voracious 

 dispositions, its quick motions, its structure. Anomaly 

 in the number of spheromcres and bearing of these 



variations upon specific distinctions. Family affinities 

 of the Hydroids and Medusa;. The Hydroids of the 

 same family bear similar relations to one another as 

 the free Medusa, p. 211-217. 



CHAPTER II. 



THE GENERA CLAVA .iVND RHIZOGETON. 



Section 1. The adult Hydroid of Ctava leptosti/la. — 

 Bibliography. Structure, p. 218-220. 



Section 2. The medusoid huds of Claim Icptostijla. ■ — 

 Tliey are the simplest among the Tubularians, and 

 never appear as independent Medusa;, p. 221 and 222. 



Section 3. Emhnjoloyi/ of Clava leplnsli/la. — It pro- 

 duces planula;. p. 222-224. 



Section 4. Rhizogclon fuxiformis. ■ — The adult hydrome- 

 dusarium. The Hydroids. The Medusa!-buds. Transfor- 

 mation of the Mcdusa?-buds into Hydroids. p. 224-22G 



CHAPTER III. 



THE GENERA HYDRACTINIA AND HALOCHARIS. 



Section 1. The hydrnid form of Hydractima polyclina. 



— Bibliography. Polymorphism. The fertile Hydroid. 



The sterile Hydroid. p. 227-235. 

 Section 2. Reproduction of Ili/ilractinia polyclina. — 



The Hydroid. The Medusoid. p. 235 and 23G. 



Section 3. Histology of Hydractinia. — The Hydroid. 

 The lasso-cells. The horny basis. The egg. The 

 spermatic particles. p. 23G-239. 



Section 4. Halocharis spiralis. — Proles hydroidea. His- 

 tology, p. 239 and 240. 



CHAPTER IV. 



THE FAMILY OF TUBULARID^. 



Section 1. General remarks upon the Tubularians. — 

 Bibliography. The family of Tubularida; cirumscribed 

 within its natural limits, p. 241-243. 



Section 2. Hybocodon prolifer. — Adult Hydroid. Proles 

 medusoidea. Embryology. Histology, p. 243-249. — 

 Since this chapter was printed, I have ascertained that 

 Euphysa belongs to the cycle of Hobocodon ; but it 

 remains to be seen whether the Medusa, here described 

 as Hybocodon, is transformed into a genuine Euphysa, 

 or the Euphysa produced from the tentacular buds 

 of an Hybocodon. 



Suction 3. Parypha crocea. — Adult Hydroid and adult 



Medusoid. Embryology. Development of the hydra. 

 Germ-basis. 5Iedusa;-buds. Histology. p. 249-265. 



Section 4. Tubularia Couthouyi. — Adult Hydroid. Full- 

 grown Medusoid. Embryology. Histology, p. 2GG-271. 



Section 5. Thamnncnidia spectabilis. — Adult Hydroid. 

 Full-grown Medusoid. Embryology. Thamnocnidia 

 tenella. p. 271-27G. 



Section 6. Corymorpha pendula. — The Hydroid. The 

 Medusa;-buds. p. 276-27S. 



Section 7. The Pennaridce. — Pennaria gibbosa. Bibli- 

 ography. The Medusa. p. 278-281. 



CHAPTER V. 



THE GENUS EUDENDRIUM OF EHRENBERO. 



Section 1. Retnarks on the Hydroids referred to the 

 genus Eudendrium, and their free Medusce. — Bibli- 

 ography. The Hydroids of this type belong to thi-ee 

 different families, p. 282-285. 



Section 2. Eudendrium dispar. — The Hydroid and the 



Medusoid. p. 285-289. 

 Section 3. Bougainvillia superciliaris. — The Hydroid, 



the Medusa3-bud, and the free Medusa, p. 289-291. 



