30 A MONOGRAPH OP THE TERTIARY POLYZOA OP VICTORIA. 



excavated in the middle so as to form two stout, sharp teeth, or with two distinct 

 teeth ; two similar denticles from the upper lip, but situated more posteriorly. 

 Avicularium replacing a zoceciuni, upper margin raised and over-arching, mandible 

 very large and semicircular. 



Var. perampla, Waters. Zooecia elongated, quadrate or hexagonal, truncated 

 above and below. 



Var. venusta, fig. 24. Branches slender. Zooecia very long, upper part enlarged, 

 lower contracted. Ovarian pore a narrow transverse slit. 



S.P. ; M.C. ; B. Recent Australia. 



In the recent typical C. rigida the zooecia are exceedingly regular in their 

 shape, being almost uniformly rhomboidal, with a sharp angle above and below ; 

 occasionally, however, they are slightly truncated. Characteristic specimens occur 

 among the fossils. The form described by Waters as C. perampla differs only in 

 the zooecia being much more elongated, with the ends straight, so that the outline 

 is hexagonal or nearly quadrate. The avicularia also seem to be rather smaller. 

 In the var. venusta the zooecia are very long, the upper part being enlarged and the 

 lower contracted, the latter part being occasionally extremely narrow. 



6. C. gracilis, Busk. PL III., fig. 26. 



Salicornaria gracilis, Busk, B.M.C., Pt. I., p. 17; C.P., Pt. I., p. 93. 



Cellaria gracilis, McG., P.Z.V., 49. 



Branches slender, cylindrical. Zooecia distant longitudinally ; separated by 

 narrow raised margins; an inner raised ridge, wide and cucullate above, less 

 prominent and forming an angle below, enclosing a depressed surface ; thyrostome 

 with the lower lip rounded and projecting forwards, with a minute denticle on each 

 side. Avicularia on special cells, with the upper margin projecting forwards. 



S.P. ; M.C. Living. Australia. 



7. C. divaricata, Busk. PL III., fig. 25. 



Salicornaria divaricata, Busk, C.P., Pt. I., p. 90; Cellaria divaricata, 

 McG., C.V. 



I have a few small fragments which I refer rather doubtfully to this recent 

 species, a full description of which is given in the " Challenger " Polyzoa. They 

 may, however, belong to C. bicomis or tcimirostris, the descriptions of which are 

 also given in the same place. The discrimination of the smaller, and in fact of all 



