rOLYZOA OF WATERWORKS, 44o 



and wei'e attached to tlie substratum, none being discovered on 

 the erect shoots. Their mode of development was not ascertained. 



Chirica (Oi, pp. 7, 8, sep.) does not describe the development 

 of the hibernacula, but records one or two interesting observa- 

 tions. He obtained them, not only at the beginning of the 

 winter, but also attached to branches of dead zocecia, floating at 

 the surface of the water in April, and he regards this as the 

 means by which the species is distributed in the spring. He 

 adds that colonies which have resulted from the germination of 

 hibernacula develop ovaries and testes at once {cf. also Kraepelin, 

 87, p. 86). 



The hibernacula of the mateinal examined by myself are, as a 

 rule, very different in form from those which have been described 

 by Dumortier and Yan Beneden, Kraepelin, Levinsen, and 

 Wesenberg-Lund. Althonghi varying much in their proportions, 

 the great majority have an elongated fusiform shape, as shown 

 in the figures on PI. LXII. It does not, however, seem to me 

 necessary to conclude that there is any specific difference between 

 the form examined by me and those of which hibernacula have 

 previously been described. Although FahocIiceUa is a light- 

 shunning organism (Allman, 56, pp. 114, 115), these specimens, 

 obtained from the interior of the pipes of a waterworks system, 

 must have been growing in absolute darkness, and under condi- 

 tions which were otherwise different from the normal habitat of 

 the sj)ecies. It would thus not be surprising if the hibernacula 

 were found to show some differences from those growing in a 

 normal environment. The conclusion that the specimens under 

 consideration should be referred to P. articulata is confirmed by 

 the fact that a single branch observed bore two hibernacula (one 

 of them shown in fig. 1) which have the form described by 

 Dumortier and Van Beneden. 



It remains to be seen, however, whether the hibernacula 

 usually developed by Paludicella in this country are typically 

 spindle-vshaped or not. Mr. C. F. Rousselet has kindly allowed 

 me to examine specimens of hibernacula, collected in Norfolk 

 by Mr. H. E. Hurrell, in his own collection. These hibernacula 

 are all of the general form described below, although they are on 

 the average rather less elongated than the specimens which have 

 come under my own observation. >Some of them have germinated, 

 in the manner desciibed by Dumortier and Van Beneden and 

 by Kraepelin. The distal end of the hibernaculum splits into 

 two valves, in order to allow of the escape of the tissues of the 

 young zooecium which grows out of the hibernaculum. It is of 

 some interest to notice, in connexion with what is said below, 

 that the stalk of the hibernaculum remains unsplit during the 

 process of germination. 



Mr. Rousselet informs me that he has never seen hibernacula 

 of any other form than the spindle-shape here described. 



The hibernacula observed by me are white in colour, although 

 some of them show sisfns of becomins: darker. The material was 



