26 Pratt, Marine Fauna of the Falklands Islands. 

 EXPLANATION OF PLATE 5. 



Fig. I. Lepralia adpressa, var. Busk. Group of zooecia, 

 inagnified about 260 diam. 

 k, knobbed cell. 



a, knobs. Characteristic of British species. 

 J", spatulate avicularium. 

 p, pores round margin between furrows. 

 Fig. 2. Single cell, magnified aboztt j8o diam. 

 C. A., circular avicularium. 

 Ch.m., chitinous mandible. 

 Fig. 3. Avicularia, magnified about j8o diam. 



a and b are aviciilaria of the ordinary beak-like 



type. 

 c and d are circtdar avicularia, showing mandible 

 in two different positions. 



Fig. 4. Porella tridentata. Portion of colony shozving dis- 

 position of zooecia, magnified about 260 diam. 



a, spatidate avicularium, 



b, lateral raised collar, meeting behind in fi 



depression. 



c, median denticle. 



d, lateral denticles. 



RAy median aviculariztm with rounded mandible. 

 Fig. 5. Single cell, magnified about j 80 diam. 



a, spatidate avicularium. 



b, median avicularium with rounded mandible. 



c, median denticle. 



d, two lateral denticles. 

 Ov, viced. 



