.388 Mr. H. M. Ward. On the Morphology and [Dec. 14 



water from the colony. The other zooids draw in water from the 

 exterior by the action of the cilia which line their cavities. This is 

 true also of the sexnal polyps in their early stages (though this 

 function is entirely lost as they become older). Hence the zooids are 

 physiologically, as well as anatomically, identical with the young 

 polyps ; they are, in other words, polyps in a state of arrested de- 

 velopment. 



The taking in of water is of vital importance to the organism, since 

 the movements of the peduncle, by which the creature creeps, are 

 effected by forcing the water to and fro. In this fact we find, 

 probably, the explanation of the very early appearance of buds upon 

 the axial polyp. 



IV. 



(20.) The facts of development, so far as they go, indicate the 

 derivation of Renilla from a form related to the Bathyptileae, which 

 probably possessed a horny axis. This view is opposed to that of 

 Kolliker, who considers that Renilla is related to the Penniformes 

 only through a primitive simple " ArGhvptilum" 



(21.) The following section contains a brief discussion of the 

 bilateral symmetry, which is strongly exhibited, both in the in- 

 dividual polyps and in the entire colony. It is shown that in both 

 cases the bilateral structure is correlated with a bilateral environment, 

 which indicates a causal relation between the two ; and I conclude 

 that the bilateral environment determines the bilateral structure. 



(22.) The last section contains a discussion of the polymorphism 

 of Renilla. An attempt is made to show that the zooids are pro- 

 bably not degenerated polyps but buds in a state of arrested develop- 

 ment, whose direct ancestors never possessed a more highly organised 

 structure than at present. 



Other theoretical questions suggested by the investigation are dis- 

 cussed under the various sections in the body of the paper. 



II. " On the Morphology and the Development of the Perithe- 

 cium of Meliola, a Genus of Tropical Epiphyllous Fungi.' 7 

 By H. Marshall Ward, B.A., Fellow of Owens College. 

 Victoria University ; late Crypt ogarnist to the Ceylon Go- 

 vernment. Communicated by W. T. Thiseltox Dyer, 

 F.R.S. Received November 28, 1882. 



(Abstract.) 



The author has investigated the life-history, strncture, and develop- 

 ment of several species of these remarkable epiphytic fungi. The 



