CONTENTS. XI 



Organs, p. 292. The Testis, where single, p. 286. ; where double, p. 287. ; where 

 provided with a Duct, p. 287. ; Varieties of the Vas deferens, p. 287. ; its Ter- 

 mination, p. 287. Further Complexities by an Epididymis, p. 288. ; by a cel- 

 lular Receptacle, or ' Vesicula,' p. 288. ; by a rudimental Penis, p. 288. ; and 

 Claspers, p. 288. Female Organs, p. 288. ; show corresponding arrests of de- 

 velopmental stages, p. 289. ; the Ovarium, p. 289. ; at first without Oviduct, 

 p. 289. ; various Conditions and Termination of Oviduct, p. 290. ' Stroma 

 Ovarii,' p. 289. Modification of Ovary in Fishes, with ovarian Gestation, p. 289. 

 Ovarian Scrotum, p. 289. Stages in development of the ' Morsus Diaboli,' 

 p. 289. Fallopian, glandular, and uterine Divisions of Oviducts in Plagios- 

 tomes, p. 290. Uterine Cotyledons, p. 291. Marsupial Pouches, p. 291. De- 

 velopment of Fishes, its Seven Stages, p. 291. Semination, p. 292. Sperma- 

 tozoa, p. 292. Germination, p. 293. Ovarian Ovum, p. 293. Fecundation, 

 p. 293. Sexual Characters and migratory Instincts, p. 294. Combats of 

 Males, p. 294. Spawning, p. 294. FoBtation, p. 295. First Changes in the 

 Ovum, Rusconi's Observations, p. 295. ; compared with the Development of the 

 Entozoon, p. 296. Rotation of Embryo in ovo, p. 296. Vertebral and viscera 1 

 germinal Layers, p. 296. ' Lamina dorsales ' and ' Laminae ventrales,' p. 296. 

 Succession of vertebral Parts, p. 297. Development of alimentary Canal, p. 297. ; 

 of Vessels, p. 297. ; of the Heart, p. 298. ; of the branchial Arches and Vessels, 

 p. 298. ; of the Brain, p. 298. ; of the Liver, the Kidneys, and generative 

 Organs, p. 298. ; of the Air-bladder and Duct, p. 299. ; of the Rostrum and 

 .Taws, p. 299. Embryonic Position of Mouth retained in Plagiostomes, and 

 embryonic Form of Head in all the ' Old Red ' Fishes, p. 299. External and 

 internal Yolk, p. 299. External Branch ias, p. 300. Singular Forms of Eggs 

 in oviparous Plagiostomes, p. 301. Ovoviviparous and viviparous Plagiostomes, 

 p. 301. Essential Distinction of latter from Mammals, p. 301. Growth of 

 Fishes, especially of the Salmon, its Metamorphoses and Migrations, p. 302. 

 Incubation of Fishes, p. 303. ; in marsupial Pouches of the Male, p. 303. 

 Nests and parental Instincts of certain Fishes, p. 303. 



