2l 



ON THE DEVELOPMENT OF TUBULIPOEA. 85 



ZooQcia more or less obviously arranged in connate series, 

 at least in well-developed colonies . . 2 



Zooecia not in connate series, even in the fertile lobes. 

 Ooeciostorae with a well-developed tube, usually more 

 or less free, the ooeciopore being larger than an orifice 

 and looking upwards T. a pert a (PI. 8, fig. 2) 



Ooeciopore much larger than an orifice, opening upwards 

 or obliquely horizontally 



T. plumosa, W. Thomps. (fig. 1) 



Ooeciostome or ooeciopore not larger or only slightly 



larger than an orifice . . .3 



fTuhe of the ooeciostome recumbent on a zooecium or 



series of zooecia, the ooeciopore opening horizontally 



or downwards . . . .4 



Tube of the ooeciostome free, greatly compressed, the 



ooeciopore being slit-like 



T. flabellaris, Fabr. (fig. 4) 

 Ooeciopore larger than an orifice, opening horizontally 



T. liliacea, Pall. (=T. serpens, auctt.) (figs. 7, 8) 

 Ooeciopore concealed, smaller than an orifice, looking 

 downwards T. phalangea, Couch (figs. 5, 6) 



The average size (in thousandths of a millimetre = ju) of 

 the ooeciopores and of the orifices is stated in the following 

 table, the greater diameter of the ooeciostome being added 

 in T. phalangea, the only species in which the ooeciopore is 

 narrower than the ooeciostome : 



4, 



It should be expressly noted that the diameter of the oldest 

 zooecia of a colony may be much smaller than that of the 

 younger zooecia. The above averages are taken from zooecia 

 which have reached their full size. 



