104 SIDNEY F. HAEMER. 



noticed in some of the proximal ovicells of the specimens of T. 

 flabellaris from Barents Sea described on p. 82. 



I have observed one or two interesting variations in this 

 species. In two or three colonies, zooecia of double the 

 normal width occur, with an orifice measuring as much as 

 380 fx in its major axis, but having the normal diameter in its 

 minor axis. In one of these cases a groove down the large 

 zooecium indicated that its size was due to the absence of the 

 septum which should normally have divided it into two zooecia. 

 A similar large zooecium was found in a colony of T. flabel- 

 laris from Greenland. I have not seen more than one of 

 these giant-zooecia in a single colony, and they do not occur at 

 all in most cases. It is not impossible that they may be 

 zooecia which made an abortive attempt to develop into ovi- 

 cells. 



In one instance an ooeciostome was recumbent on a giant 

 zooecium (cf. the remarks given in Waters' paper, 45, p. 277), 

 but there was no similar relation in the other cases. Walford 

 (42, p. 80) has characterised his genus Cisternifera (said to 

 be Cheilostomatous) by the occurrence of giant-zooecia in the 

 colbny, and has in the same place (p. 79, pi, v, figs. 14, 15) 

 described similar giant-zooecia or "cistern-cells" in '^so-called 

 Diastoporse '^ from the Great Oolite. These latter, at any 

 rate, appear to me to correspond with the large zooecia of T. 

 aperta and T. flabellaris. 



A more interesting variation was noticed in two colonies in 

 which an ovicell had developed accessory boeciostomes (fig. 2). 

 Since the ovicell of Tubulipora is an enlarged zooecium, its 

 Goeciopore is homologous with a normal orifice, and it follows 

 that an ovicell should have only one ooeciostome. This is 

 actually the case in most species, and in most colonies which I 

 have seen of T. aperta. When the growth of the ovicell is 

 completed, each of the lobes other than that ending in the 

 ooeciostome normally becomes closed by a porous calcareous 

 film. In the abnormal colonies of T. aperta, however^ one or 

 more of these lobes has not closed completely, but has grown 

 at its distal end into a tube, which may completely simulate 



