ON THE DEVELOPMENT OP TUBULIPOEA. 97 



an extreme case of this kind. The smaller colonies have 

 simpler ovicells, but this is also the case in other species. 



My Salcombe specimens were dredged in March and April; 

 and an examination of this material gives some hints with 

 regard to the meaning of the differences in size. A very large 

 number of colonies found on shells were small and pyriform, 

 although in many cases possessing a mature ovicell ; while 

 other small colonies consisted of only two or three lobes. 

 These colonies were nearly all brown, and more or less en- 

 crusted with foreign matter. Here and there an old lobe had 

 recommenced to grow, and had given rise to a fresh and clean 

 lobe, whose brilliant white colour (in spirit specimens) forms 

 the most striking contrast with the older lobes. The colonies 

 of Tubulipora have in fact the power, which is probably 

 common to all Cyclostomes, of regenerating new zooecia from 

 various parts of the old colony (cf. 13, p. 141). In the species 

 now under consideration a small part of the edge of the old 

 colony here and there becomes active, so that a series of fresh 

 lobes, with narrow bases, may be seen growing out from 

 various parts. These lobes have in many cases acquired a 

 considerable size by the beginning of April, and have developed 

 mature ovicells. A few quite young, healthy colonies were 

 found amongst these specimens. It is probable that these 

 last were colonies which had recently commenced their ex- 

 istence, that the brown specimens belonged to a previous year, 

 and that the fresh lobes proceeding from them were entirely 

 recent growths. If this is a correct inference, it may be 

 suggested that the small brown colonies were produced late 

 in the year when the temperature was becoming low, so that 

 although they became mature so far as the external characters 

 of their ovicells were concerned, they were unable to grow large. 

 There was of course no doubt that the finely developed speci- 

 mens were actively growing when they were dredged. 



I think it probable, therefore, that the diflference in the 

 development of the entire colony may, in some cases at least, 

 be of a seasonal nature. 



I may here refer to some interesting remarks which have 



VOL. 41, PART 1. KEW 8ER. G 



