290 Miscellaneous. 



chemical constitution of the surrounding fluid, and a consequent 

 disturbance in its stability. 



The reproductive system of Cordylophora consists of ovoid cap- 

 sules situated on the ultimate branches at some distance behind the 

 polypes ; some of these capsules contain ova, others spermatozoa ; 

 they are plainly homologous with the ovigerous sacs of the marine 

 TubulariadcB ; they present a very evident, though disguised medusoid 

 structure, having a hollow cylindrical body, whose cavity is conti- 

 nuous with that of the polype-stem, projecting into them below, and 

 representing the proboscidiform stomach of a Medusa, while a sy- 

 stem of branched tubes which communicate at their origin with the 

 cavity of the hollow organ, must be viewed as the homologues of 

 the radiating gastro-vascular canals, and the proper walls of the 

 capsule will then represent the disc. From comparative observations 

 made on other genera of Hydroida, the author maintains the presence 

 of a true medusoid structure in the fixed ovigerous vesicles of all the 

 genera he has examined, and he arrives at the generalization, that for 

 the production of true ova in the hydroid zoophytes, a particular 

 form of zooid is necessary, in which the ordinary polype -structure 

 becomes modified, and presents, instead, a more or less obvious 

 medusoid conformation. Hydra being at present the only genus 

 which appears to offer an exception to this law, though the author 

 believes that the exception is only apparent, and that further obser- 

 vations will enable us to refer the reproductive organization of this 

 zoophyte to the same type with that of Cordylophora and the marine 

 Hydroida. The author has satisfied himself that the ova-like bodies 

 contained in the capsules of Cordylophora are true ova, and not 

 gemma: ; he has demonstrated in them a distinct germinal vesicle, 

 and has witnessed the phaenomenon of yelk-cleavage ; and the paper 

 details the development of the embryo to the period of its escape 

 from the capsule in the form of a free- swimming ciliated animacule, 

 and traces its subsequent progress into the condition of the adult 

 zoojihyte. 



MISCELLANEOUS. 

 On the Monstrosity of a Rose. By J. T. Arlidge, A.B. 



With few exceptions the flowers on a standard-rose, growing on a 

 lawn, failed this summer to exhilrit good ' blooms,' and presented 

 various degrees and forms of monstrosity. This occurrence may be 

 attributed to the wet season stimulating the tree to the production of 

 wood instead of flowers. It should, however, be noted, that neigh- 

 bouring rose-trees, growing under precisely the same circumstances, 

 but of different species, produced their proper flowers ; with, however, 

 a prevailing tendency to abortive petal-growth, and the production of 

 the condition known as the ' green-eye.' 



In the tiee in question the most remarkable example was that of a 



