142 SIDNEY F. HARMER. 



all cases due to the upgrowth of a zooecium which interrupts 

 the growth of the ovicell. 



The ovicell contains (as in stage E) two principal cavities, — 

 firstly, the cavity of the embryophore ; and secondly, the 

 cavity in which the embryophore lies. The latter may be 

 regarded as the body-cavity of the original fertile zocEcium, 

 and it is constantly extending itself between the series of 

 zooecia by the growth of the edge of the ovicell. The growth 

 of this cavity is more energetic during this stage than that of 

 the embryophore ; so that each lobe of the latter merely enters 

 the base of the corresponding lobe of the entire ovicell. 



In one ovicell in stage F where this arrangement was 

 obvious, the axial lobe of the entire ovicell had elongated 

 greatly, while the corresponding lobe of the embryophore only 

 just entered its base. The vestibule had accordingly been 

 greatly elongated (to 400 fx), so as to retain its connection 

 both with the terminal membrane and with the embryophore. 

 The vestibule is lined with a chitinous ectocyst, and opens to 

 the exterior by joining the terminal membrane. The fertile 

 brown body lies freely in the middle of the large cavity of the 

 distal end of the embryophore. The embryo, about 225 /n 

 long, lies in the proximal cylindrical part of the embryophore, 

 and is clearly dividing into a number of secondary embryos. 

 Giant-cells, similar to those of Crisia and of Lichenopora, 

 occur in the position of the original embryonic follicle. 



The total length of a trifid embryophore during this stage 

 was 800 fx, and the distance from tip to tip of its lateral lobes 

 was 720 fi. The brown body remains distinguishable during 

 this stage, usually lying freely in the cavity of the embryo- 

 phore. The partially divided primary embryo in one case 

 formed a large, more or less spherical mass, with a diameter 

 of 305 fx. 



Stage G. — Fully formed Ovicell. 



This stage, which corresponds with the figures given of the 

 mature colonies of the several species, is illustrated by fig. 33, 

 from a decalcified preparation of T. plumosa. The embryo- 



