Plate 9 



Maivsonia extensalata, new species, and M. memhranacea Thornely 



(Figures drawn with aid of camera lucida) 



Figure A: Mazvsonia extensalata. new species. View of outer surface of a\'iculai-ian man- 

 dible showing sharp knife-edge keel and curved tip. Scale a. 



Figure B: Mazvsonia extensalata. A fairh' young zooecium. Depressed area between i' 

 orifice rim and distal zooecial wall fills in and becomes heavih' calcified in older zooecia, t 

 merging with the curved cryptocyst ridges. Scale a. 



Figure C: Mawsonia extensalata. /Vvicularian mandible. Scale a. 



Figure D: Mawsonia extensalata. Operculum tilted slightly to show reinforcements.;' 

 Scale b. 



Figure E: Mawsonia extensalata. Operculum seen from inner surface. Flange around; 

 inner rim is especialh' extended at the two sides into areas for muscle attachment. Scale h. 



Figure F: Mawsonia membranacea. Side view of avicularian mandible showing the f 

 curved tip. Scale c. 



Figure G: Mawsonia membranacea. Zooecium. Operculum is in the orifice, and has two : 

 light-colored or thinner oval areas for articulation with orificial condyles. Prominent smooth 

 parentheses lines immediately enclose the orifice on two sides; around them curve the ^ 

 prominent, roughened, calcified, cryptocyst ridges. Scale a. 



Figure H: Mazvsonia membranacea. An older zooecium. Not many zooecia in che a 

 colony have such sharply raised mural rims. The two orificial condyles show plainly because i 

 operculum is missing. Scale a. 



Figure I: Mawsonia membranacea. Outside view of a\-icularian mandible. Scale a. 



Figure J: Mawsonia membranacea. Avicularium and mandible. Scale a. 



Figure K: Mazvsonia membranacea. Typical avicularium showing an odd opesia or ii 

 opening to interior. Scale a. 



Figure L: Mazvsonia membranacea. An avicularium. Scale (/. 



Figure M: Mawsonia membranacea. Upper two-thirds of the only colony fragment of 

 the species showing arrangement of zooecia and avicularia. From one zooecium springs a ; 

 thin-walled rootlet. An avicularium is directly above, to the left of the same zooecium. 

 Scale e. 



