ON THE DEVELOPMENT OF TUBULIPORA. 99 



space in the centre. I have had no opportunity of examining 

 cases of this kind. 



Hincks (18, p. 447) has referred to a curious lobed Tubuli- 

 pora, about an inch in diameter, which he has met with in 

 Salcombe Bay. I have obtained some specimens which appear 

 to correspond with Mr. Hincks's description. One or two of 

 these colonies were from the Salcombe Estuary, and had the 

 ooeciostomes of T. phalangea. Two others were sent to me 

 from Plymouth by Mr. Church, and had the ooeciostomes of 

 T. plumosa. The variety is a very curious one, and is 

 characterised by its nearly circular outline and by the great 

 crowding of the zocecia, the series being placed very close 

 together, and the lobes of the well-branched ovicells being 

 correspondingly narrow. On closer examination a consider- 

 able difference (no doubt specific) between the Plymouth and 

 the Salcombe specimens becomes apparent. A perfect colony 

 of the former measures about 15 mm. in diameter; it is com- 

 posed of twelve well-marked lobes, and closely resembles the 

 form of T. plumosa which is found on Saccorhiza. These 

 lobes can be readily made out without any magnification, 

 whereas the Salcombe specimens do not appear obviously lobed 

 when examined with the naked eye. 



I regard this variety as due to an excessive growth of the 

 edge of the colony, resulting, by the mutual pressure of the 

 lobes, in a crowding of the zooecia, and in the acquirement of 

 a circular form. This appears to me to be a further instance 

 of the tendency of different species ofTubulipora to assume 

 the same general form as the result of some unknown factors 

 in the environment. 



T, flabellaris, Fabricius (fig. 4, described on p. 82). 



Tubipora flabellaris, Fabr. (11, p. 430). 



Tubulipora flabellaris, Smitt (40, p. 401, pi. ix, figs. 6—8). 



? T. flabellaris, Levinseu (26, p. 76, pi. vii, figs. 1—3). 



Zoarium entirely adnata, more or less fan-shaped in form in well-developed 

 specimens. Stunted colonies may occur, as in the preceding species. Some 

 of the zooecia are free, others are in connate series, which are more or less 



