Botanical Society of Edinburgh, 313 



the marine Caulerpites more tlian any other described by Brongniart. 

 The genus was interesting, as embracing the Prasium of Aristotle, 

 which, until recently translated either a Leek or an Onion, was now 

 known to be Caulerpa prolifera, a Mediterranean species. 



2. " On the Analogy between the Processes of Reproduction in the 

 Plant and in the Hydroid Zoophyte," by Professor Wyville Thom- 

 son. Dr. Thomson stated that the term *' Zoophyte" had been ori- 

 ginally applied to indicate an intermediate position which these beings 

 were supposed to hold between the animal and vegetable kingdoms ; 

 that subsequently their animal nature had been completely made 

 out ; and that the old term Zoophyte had then only been retained as 

 an innocent remnant of the superstition of those dark ages ; that 

 latterly, however, some strange analogies had been made out between 

 the mode of growth of Zoophytes and of the higher tribes of plants, 

 which seemed to indicate that they had some right to their old desig- 

 nation ; that when there was a strong tendency, as in Zoophytes and 

 in Plants, to the indefinite multiplication of similar parts, there was 

 a tendency likewise to the development of these parts according to 

 the same laws. He alluded to the union in these indefinitely repeated 

 parts of the functions of respiration and assimilation in both tribes ; 

 to the tendency to spiral arrangement of parts of the polypidom ; and 

 to the formation of corpuscles bearing ova, and which are due to the 

 modification or compression of ordinary branches with their buds. 

 Dr. Thomson said that he had had opportunities of observing the 

 process of reproduction in several species of the genus Campanularia ; 

 he described the peculiar reproductive process in this family, which 

 has been called an " alternation of generations," and alluded to the 

 discovery by Schultze of male individuals of the various species form- 

 ing capsules containing spermatozoids. He believed that he had 

 been able to make out distinctly three varieties in the development of 

 the medusoids in three species of Campanularia {gelatinosa, geni- 

 culata, and volubilis). In the first, the capsule of tlie female indi- 

 vidual first appears with a free hollow rod in the centre, like the free 

 central placenta in the Primulacece. This rod is covered by a par- 

 tially developed membrane. After a time, a round mass pullulates 

 from this rod beneath this membrane. A communication at first 

 exists between the canal in the centre of the rod, and this globe ; 

 this communication is at length closed up, and the projection assumes 

 the form of a true ovarian ovum with a distinct germinal vesicle. 

 The germinal vesicle then disappears, and is gi-adually replaced by 

 a mass of embryo cells. This mass shows very well the usual process 

 of merismatic division. It afterwards becomes developed into a free 

 ciliated embryo, which fixes closely to a solid body and is quickly 

 developed into a polyp. The contents of the male capsules are 

 formed almost in a like manner, only the original spherical bodies 

 become filled with a substance resembling fo villa, which escapes into 

 the water, without any secondary embryonic formation. In the 

 second species, the embryo is not developed in the capsule, but a 

 mass which Dr. Thomson regarded as homologous with the " ovum" 

 in the former species, is extended from the mouth of the capsule, in 



